gen1recomp/docs/gold-walkthrough/asm-walk/section-28-routes-19-20-and-viridian-city-gym.md

Section 28 - Routes 19-20 and Viridian City Gym

Source: ../section-28-routes-19-20-and-viridian-city-gym.txt (the FAQ numbers this chapter "34 > Routes 19-20 and Viridian City Gym") Maps covered: MAP_ROUTE_20, MAP_ROUTE_19, MAP_ROUTE_19_FUCHSIA_GATE, MAP_VIRIDIAN_CITY, MAP_VIRIDIAN_POKECENTER_1F, MAP_VIRIDIAN_GYM Badges / key milestones in this section: EARTHBADGE (ENGINE_EARTHBADGE) from Blue in Viridian Gym, EVENT_BEAT_BLUE, five optional Swimmer battles on Routes 19/20. This is the 16th badge, which is what maps/OaksLab.asm reads to open Mt. Silver in a later section.

Map group / id pairs a bot needs (from constants/map_constants.asm):

Map constant	group	id
MAP_ROUTE_19_FUCHSIA_GATE	6 (CINNABAR, constants/map_constants.asm:175)	3
MAP_ROUTE_19	6	5
MAP_ROUTE_20	6	6
MAP_VIRIDIAN_CITY	23 (VIRIDIAN, constants/map_constants.asm:420)	3
MAP_VIRIDIAN_GYM	23	4
MAP_VIRIDIAN_POKECENTER_1F	23	9

Coordinate convention reminder: warp_event / coord_event / bg_event / object_event all take x, y in map cell coordinates, 0-based from the top-left (macros/scripts/maps.asm:63, :79, :97, :113). A map that is W, H blocks is 2W, 2H cells. changeblock also takes cell coordinates and halves them internally (engine/overworld/scripting.asm:2030 Script_changeblock, home/map.asm:2099 GetBlockLocation).

1. Route order

#	Map constant	asm file	Enter via	Leaves via	Why (walkthrough beat)
0	MAP_SEAFOAM_GYM	maps/SeafoamGym.asm (previous section)	-	its exit warp back to Route 20 warp 1	Blaine's gym sits on Route 20; the previous section ends there
1	MAP_ROUTE_20	maps/Route20.asm	Seafoam Gym exit -> Route 20 warp 1 (38, 7), or the west connection from Cinnabar Island	east map connection to Route 19 (data/maps/attributes.asm:285, offset -9)	"East on Route 20 and to Route 19 are optional ... Surf down and right to face the swimmer in the water" (Lori, then Nicole)
2	MAP_ROUTE_19	maps/Route19.asm	west map connection from Route 20 (data/maps/attributes.asm:289, offset 9)	Fly (walkthrough), or warp 1 (7, 3) -> ROUTE_19_FUCHSIA_GATE warp 3, or the north connection to Fuchsia City	"You'll find a drowning guy next to a girl" (Tucker, Dawn, then Jerome). "Fly back to Viridian City instead"
2a	MAP_ROUTE_19_FUCHSIA_GATE	maps/Route19FuchsiaGate.asm	Route 19 warp 1	warps 1/2 (4, 0) / (5, 0) -> FUCHSIA_CITY warps 10 / 11	Only referenced by the walkthrough's "blocked ... south of Fuchsia City" line; see section 6
3	MAP_VIRIDIAN_CITY	maps/ViridianCity.asm	Fly (ENGINE_FLYPOINT_VIRIDIAN, spawn (23, 26))	warp 5 (23, 25) -> Pokecenter; warp 1 (32, 7) -> gym	"fly back to Viridian City ... First, heal at the Pokémon Center"
4	MAP_VIRIDIAN_POKECENTER_1F	maps/ViridianPokecenter1F.asm	Viridian warp 5	warps 1/2 (3, 7) / (4, 7) -> Viridian warp 5	Heal before and after Blue
5	MAP_VIRIDIAN_GYM	maps/ViridianGym.asm	Viridian warp 1 (32, 7)	warps 1/2 (4, 17) / (5, 17) -> Viridian warp 1	"GYM LEADER BLUE ... You get: Earth Badge, 5,800G"

Spillover: the closing line "There are still a few things you can do before you clear Kanto" points at maps/OaksLab.asm:26 (readvar VAR_BADGES / ifequal NUM_BADGES, .OpenMtSilver), which belongs to the next section. Nothing past the Viridian Gym exit is described here.

2. Maps

MAP_ROUTE_20

• Script: maps/Route20.asm
• Blocks: maps/Route20.blk (data/maps/blocks.asm:118 Route20_Blocks)
• Header: data/maps/maps.asm:197 -> TILESET_KANTO, ROUTE, LANDMARK_ROUTE_20, MUSIC_ROUTE_3, phone FALSE, PALETTE_AUTO, FISHGROUP_OCEAN
• Dimensions: constants/map_constants.asm:181 map_const ROUTE_20, 30, 9 (30x9 blocks = 60x18 cells)
• Connections: data/maps/attributes.asm:283-285 - west CinnabarIsland (CINNABAR_ISLAND, offset 0), east Route19 (ROUTE_19, offset -9). No north/south.
• Map events block: Route20_MapEvents, sym 4e:4ecd

Warps (def_warp_events)

idx	x	y	destination map	dest warp
1	38	7	SEAFOAM_GYM	1

Coord events (def_coord_events) - none (def_coord_events is empty).

BG events (def_bg_events)

x	y	type	script/item
37	11	BGEVENT_READ	CinnabarGymSign (sym 4e:4d3a) -> CinnabarGymSignText

Object events (def_object_events)

const	sprite	x	y	movement	type	script label	event flag
ROUTE20_SWIMMER_GIRL1	SPRITE_SWIMMER_GIRL	52	8	SPRITEMOVEDATA_SPINRANDOM_FAST (radius 0,0)	OBJECTTYPE_TRAINER, sight 3, PAL_NPC_GREEN	TrainerSwimmerfNicole (sym 4e:4cfe)	-1 (always present)
ROUTE20_SWIMMER_GIRL2	SPRITE_SWIMMER_GIRL	45	13	SPRITEMOVEDATA_SPINRANDOM_FAST (radius 0,0)	OBJECTTYPE_TRAINER, sight 3, PAL_NPC_GREEN	TrainerSwimmerfLori (sym 4e:4d12)	-1
ROUTE20_SWIMMER_GUY	SPRITE_SWIMMER_GUY	12	13	SPRITEMOVEDATA_SPINRANDOM_FAST (radius 0,0)	OBJECTTYPE_TRAINER, sight 3, PAL_NPC_RED	TrainerSwimmermCameron (sym 4e:4d26)	-1

Scripts of interest

• Route20_MapScripts (maps/Route20.asm:6): no scene scripts; one callback, callback MAPCALLBACK_NEWMAP, Route20ClearRocksCallback.
• Route20ClearRocksCallback (maps/Route20.asm:12, sym 4e:4cfa): two opcodes, setevent EVENT_CINNABAR_ROCKS_CLEARED then endcallback. This is the single most load-bearing fact on this map: merely entering Route 20 for the first time permanently clears the Route 19 boulders. There is no other setter of that flag anywhere in maps/.
• The three trainer scripts are the stock pattern: trainer <CLASS>, <ID>, <EVENT>, SeenText, BeatenText, 0, .Script, and .Script is endifjustbattled / opentext / writetext <AfterBattleText> / waitbutton / closetext / end. No items, no flags beyond the trainer's own beat flag.

Flags and events

constant	defined in	read/written by	meaning for a bot
EVENT_CINNABAR_ROCKS_CLEARED	constants/event_flags.asm:214	set by Route20ClearRocksCallback; read by Route19ClearRocksCallback, Route19Fisher1Script, Route19Fisher2Script, Route19FuchsiaGateOfficerScript	Once set, the six Route 19 boulder blocks are never placed
EVENT_BEAT_SWIMMERF_NICOLE	constants/event_flags.asm:487	TrainerSwimmerfNicole	One-time battle
EVENT_BEAT_SWIMMERF_LORI	constants/event_flags.asm:488	TrainerSwimmerfLori	One-time battle
EVENT_BEAT_SWIMMERM_CAMERON	constants/event_flags.asm:957	TrainerSwimmermCameron	One-time battle; the walkthrough never mentions him

Items - none on this map (the only bg_event is a readable sign; no hiddenitem, no item balls).

Trainers

const	class	id	party (data/trainers/parties.asm label)	script label	rematch/phone
SWIMMERF / LORI	27 (constants/trainer_constants.asm:375)	LORI = SwimmerFGroup entry 15	data/trainers/parties.asm:1781 SwimmerFGroup (sym 0e:69c7), TRAINERTYPE_NORMAL: L32 STARMIE, L32 STARMIE	TrainerSwimmerfLori	none (no phone_call / rematch entry)
SWIMMERF / NICOLE	27	NICOLE = SwimmerFGroup entry 14	TRAINERTYPE_NORMAL: L29 MARILL, L29 MARILL, L32 LAPRAS	TrainerSwimmerfNicole	none
SWIMMERM / CAMERON	26 (constants/trainer_constants.asm:352)	CAMERON = SwimmerMGroup entry 17	data/trainers/parties.asm:1640 SwimmerMGroup (sym 0e:68a8), TRAINERTYPE_NORMAL: L34 MARILL	TrainerSwimmermCameron	none

Prize money: data/trainers/attributes.asm:227 gives class Swimmerm base reward 2, :233 gives Swimmerf base reward 5, no held items. engine/battle/read_trainer_party.asm:300 ComputeTrainerReward = base x level of the last mon, and engine/battle/core.asm:2340-2362 pays that quarter out four times, so the wallet figure is 4 x base x level: Lori and Nicole 4 x 5 x 32 = 640 (matches the FAQ), Cameron 4 x 2 x 34 = 272.

Wild encounters

• Surfing: data/wild/kanto_water.asm:54 def_water_wildmons ROUTE_20, encounter rate 6 percent: L35 TENTACOOL, L30 TENTACOOL, L35 TENTACRUEL. No morn/day/nite split (water tables have a single slot list).
• No entry in data/wild/kanto_grass.asm (the map has no grass), none in data/wild/treemons.asm.
• Fishing: header fish group is FISHGROUP_OCEAN (data/maps/maps.asm:197), data/wild/fish.asm .Ocean_Old / .Ocean_Good / .Ocean_Super (lines 42-55): Old = MAGIKARP/MAGIKARP/TENTACOOL L10; Good = MAGIKARP L20, TENTACOOL L20, CHINCHOU L20, time group 2; Super = CHINCHOU L40, time group 3, TENTACRUEL L40, LANTURN L40.

MAP_ROUTE_19

• Script: maps/Route19.asm
• Blocks: maps/Route19.blk (data/maps/blocks.asm:48 Route19_Blocks)
• Header: data/maps/maps.asm:196 -> TILESET_KANTO, ROUTE, LANDMARK_ROUTE_19, MUSIC_ROUTE_3, phone FALSE, PALETTE_AUTO, FISHGROUP_SHORE
• Dimensions: constants/map_constants.asm:180 map_const ROUTE_19, 10, 18 (10x18 blocks = 20x36 cells)
• Connections: data/maps/attributes.asm:287-289 - north FuchsiaCity (FUCHSIA_CITY, offset 0), west Route20 (ROUTE_20, offset 9). No south/east.
• Map events block: Route19_MapEvents, sym 4e:535c

Warps (def_warp_events)

idx	x	y	destination map	dest warp
1	7	3	ROUTE_19_FUCHSIA_GATE	3

Coord events (def_coord_events) - none.

BG events (def_bg_events)

x	y	type	script/item
11	13	BGEVENT_READ	Route19Sign (sym 4e:4fa0) -> Route19SignText
11	1	BGEVENT_READ	CarefulSwimmingSign (sym 4e:4fa3) -> CarefulSwimmingSignText

Object events (def_object_events)

const	sprite	x	y	movement	type	script label	event flag
ROUTE19_SWIMMER_GIRL	SPRITE_SWIMMER_GIRL	9	23	SPRITEMOVEDATA_STANDING_LEFT (radius 0,0)	OBJECTTYPE_TRAINER, sight 0, PAL_NPC_GREEN	TrainerSwimmerfDawn (sym 4e:4f28)	-1
ROUTE19_SWIMMER_GUY1	SPRITE_SWIMMER_GUY	13	28	SPRITEMOVEDATA_SPINRANDOM_FAST (radius 0,0)	OBJECTTYPE_TRAINER, sight 3, PAL_NPC_RED	TrainerSwimmermHarold (sym 4e:4f3c)	-1
ROUTE19_SWIMMER_GUY2	SPRITE_SWIMMER_GUY	11	17	SPRITEMOVEDATA_SPINRANDOM_FAST (radius 0,0)	OBJECTTYPE_TRAINER, sight 3, PAL_NPC_RED	TrainerSwimmermJerome (sym 4e:4f50)	-1
ROUTE19_SWIMMER_GUY3	SPRITE_SWIMMER_GUY	8	23	SPRITEMOVEDATA_STANDING_UP (radius 0,0)	OBJECTTYPE_TRAINER, sight 0, PAL_NPC_RED	TrainerSwimmermTucker (sym 4e:4f64)	-1
ROUTE19_FISHER1	SPRITE_FISHER	9	5	SPRITEMOVEDATA_STANDING_DOWN (radius 0,0)	OBJECTTYPE_SCRIPT (sight field 1, unused)	Route19Fisher1Script (sym 4e:4f78)	-1
ROUTE19_FISHER2	SPRITE_FISHER	11	5	SPRITEMOVEDATA_WALK_LEFT_RIGHT (radius 1,0)	OBJECTTYPE_SCRIPT (sight field 1, unused)	Route19Fisher2Script (sym 4e:4f8c)	-1

Note for a bot: Tucker (8, 23) and Dawn (9, 23) both have sight range 0, so they never initiate a battle by line of sight. They must be talked to, which is exactly the walkthrough's "Talk to the guy for a battle" / "talk to the girl to battle her". Harold and Jerome have sight 3 and will pull the player in.

Scripts of interest

• Route19_MapScripts (maps/Route19.asm:9): no scene scripts; one callback, callback MAPCALLBACK_TILES, Route19ClearRocksCallback.
• Route19ClearRocksCallback (maps/Route19.asm:15, sym 4e:4f09): checkevent EVENT_CINNABAR_ROCKS_CLEARED / iftrue .Done, otherwise six changeblock calls writing block $7a (a rock) at cells (6, 6), (8, 6), (10, 6), (12, 8), (4, 8), (10, 10) - i.e. blocks (3, 3), (4, 3), (5, 3), (6, 4), (2, 4), (5, 5). Block $7a in data/tilesets/kanto_collision.asm:123 is tilecoll WALL, WALL, WALL, WALL, so all four quadrants are solid; these are impassable terrain, not Strength boulders. Because this is MAPCALLBACK_TILES it re-runs on every map load, and because EVENT_CINNABAR_ROCKS_CLEARED is set by simply walking onto Route 20, by the time this section runs the rocks are already gone.
• Route19Fisher1Script / Route19Fisher2Script (maps/Route19.asm:71 / :87): faceplayer / opentext / checkevent EVENT_CINNABAR_ROCKS_CLEARED / iftrue .RocksCleared. Flavor only, no flags written, no items.
• The four trainer scripts follow the same endifjustbattled pattern as Route 20's.

Flags and events

constant	defined in	read/written by	meaning for a bot
EVENT_CINNABAR_ROCKS_CLEARED	constants/event_flags.asm:214	read by Route19ClearRocksCallback and both Fisher scripts	Gate on whether the north half of Route 19 is walkable
EVENT_BEAT_SWIMMERF_DAWN	constants/event_flags.asm:485	TrainerSwimmerfDawn	One-time battle
EVENT_BEAT_SWIMMERM_HAROLD	constants/event_flags.asm:941	TrainerSwimmermHarold	One-time battle; not mentioned by the walkthrough
EVENT_BEAT_SWIMMERM_JEROME	constants/event_flags.asm:954	TrainerSwimmermJerome	One-time battle
EVENT_BEAT_SWIMMERM_TUCKER	constants/event_flags.asm:955	TrainerSwimmermTucker	One-time battle

Items - none. Both bg_events are BGEVENT_READ signs; there is no hiddenitem and no item ball on this map.

Trainers

const	class	id	party (data/trainers/parties.asm label)	script label	rematch/phone
SWIMMERM / TUCKER	26	SwimmerMGroup entry 15	TRAINERTYPE_NORMAL: L30 SHELLDER, L34 CLOYSTER	TrainerSwimmermTucker	none
SWIMMERF / DAWN	27	SwimmerFGroup entry 12	TRAINERTYPE_NORMAL: L34 SEAKING	TrainerSwimmerfDawn	none
SWIMMERM / JEROME	26	SwimmerMGroup entry 14	TRAINERTYPE_NORMAL: L26 SEADRA, L28 TENTACOOL, L30 TENTACRUEL, L28 GOLDEEN	TrainerSwimmermJerome	none
SWIMMERM / HAROLD	26	SwimmerMGroup entry 1	TRAINERTYPE_NORMAL: L32 REMORAID, L30 SEADRA	TrainerSwimmermHarold	none

Prize money using the same 4 x base x last-mon level rule: Tucker 4 x 2 x 34 = 272, Dawn 4 x 5 x 34 = 680, Jerome 4 x 2 x 28 = 224, Harold 4 x 2 x 30 = 240. The first three match the FAQ exactly.

Wild encounters

• Surfing: data/wild/kanto_water.asm:47 def_water_wildmons ROUTE_19, encounter rate 6 percent: L35 TENTACOOL, L30 TENTACOOL, L35 TENTACRUEL.
• No grass table, no headbutt table.
• Fishing: FISHGROUP_SHORE (data/maps/maps.asm:196), data/wild/fish.asm .Shore_Old / .Shore_Good / .Shore_Super (lines 28-40): Old = MAGIKARP/MAGIKARP/KRABBY L10; Good = MAGIKARP L20, KRABBY L20 (x2), time group 0; Super = KRABBY L40, time group 1, KRABBY L40, KINGLER L40.

MAP_ROUTE_19_FUCHSIA_GATE

Included because the walkthrough's "blocked by those boulders south of Fuchsia City" line points at it. The walkthrough never actually enters it.

• Script: maps/Route19FuchsiaGate.asm
• Blocks: maps/Route19FuchsiaGate.blk (data/maps/blocks.asm:204 Route19FuchsiaGate_Blocks)
• Header: data/maps/maps.asm:194 -> TILESET_GATE, GATE, LANDMARK_ROUTE_19, MUSIC_ROUTE_3, phone FALSE, PALETTE_DAY, FISHGROUP_SHORE
• Dimensions: constants/map_constants.asm:178 map_const ROUTE_19_FUCHSIA_GATE, 5, 4 (10x8 cells)
• Connections: none (data/maps/attributes.asm:512 has no connection rows)

Warps (def_warp_events)

idx	x	y	destination map	dest warp
1	4	0	FUCHSIA_CITY	10
2	5	0	FUCHSIA_CITY	11
3	4	7	ROUTE_19	1
4	5	7	ROUTE_19	1

Coord events - none. BG events - none.

Object events

const	sprite	x	y	movement	type	script label	event flag
ROUTE19FUCHSIAGATE_OFFICER	SPRITE_OFFICER	0	4	SPRITEMOVEDATA_STANDING_RIGHT (radius 0,0)	OBJECTTYPE_SCRIPT, PAL_NPC_BLUE	Route19FuchsiaGateOfficerScript	-1

Scripts of interest

• Route19FuchsiaGateOfficerScript (maps/Route19FuchsiaGate.asm:9): faceplayer / opentext / checkevent EVENT_CINNABAR_ROCKS_CLEARED / iftrue .RocksCleared, then one of two texts. He is at (0, 4), off to the side of the (4, ...) / (5, ...) walkway, so he blocks nothing. There is no coord event and no movement-blocking script in this gate: the officer is flavor, and the actual road closure is the changeblock rocks on Route 19 itself.

MAP_VIRIDIAN_CITY

• Script: maps/ViridianCity.asm
• Blocks: maps/ViridianCity.blk (data/maps/blocks.asm:235 ViridianCity_Blocks)
• Header: data/maps/maps.asm:457 -> TILESET_KANTO, TOWN, LANDMARK_VIRIDIAN_CITY, MUSIC_VIRIDIAN_CITY, phone FALSE, PALETTE_AUTO, FISHGROUP_POND
• Dimensions: constants/map_constants.asm:423 map_const VIRIDIAN_CITY, 20, 18 (40x36 cells)
• Connections: data/maps/attributes.asm:259-261 - north Route2 (ROUTE_2, offset 5), south Route1 (ROUTE_1, offset 10), west Route22 (ROUTE_22, offset 4). No east.
• Map events block: ViridianCity_MapEvents, sym 4e:4486
• Fly target: data/maps/flypoints.asm:19 db LANDMARK_VIRIDIAN_CITY, SPAWN_VIRIDIAN; data/maps/spawn_points.asm:15 spawn VIRIDIAN_CITY, 23, 26 (the Pokecenter doorstep)

Warps (def_warp_events)

idx	x	y	destination map	dest warp
1	32	7	VIRIDIAN_GYM	1
2	21	9	VIRIDIAN_NICKNAME_SPEECH_HOUSE	1
3	23	15	TRAINER_HOUSE_1F	1
4	29	19	VIRIDIAN_MART	2
5	23	25	VIRIDIAN_POKECENTER_1F	1

Coord events (def_coord_events) - none.

BG events (def_bg_events)

x	y	type	script/item
17	17	BGEVENT_READ	ViridianCitySign
27	7	BGEVENT_READ	ViridianGymSign (sym 4e:4053) - "LEADER: ... The rest of the text is illegible"
19	1	BGEVENT_READ	ViridianCityWelcomeSign
21	15	BGEVENT_READ	TrainerHouseSign
24	25	BGEVENT_READ	ViridianCityPokecenterSign (jumpstd PokecenterSignScript)
30	19	BGEVENT_READ	ViridianCityMartSign (jumpstd MartSignScript)

Object events (def_object_events)

const	sprite	x	y	movement	type	script label	event flag
VIRIDIANCITY_GRAMPS1	SPRITE_GRAMPS	18	5	SPRITEMOVEDATA_WANDER (radius 2,2)	OBJECTTYPE_SCRIPT	ViridianCityCoffeeGramps	-1
VIRIDIANCITY_GRAMPS2	SPRITE_GRAMPS	30	8	SPRITEMOVEDATA_STANDING_DOWN	OBJECTTYPE_SCRIPT, PAL_NPC_BLUE	ViridianCityGrampsNearGym (sym 4e:401e)	-1
VIRIDIANCITY_FISHER	SPRITE_FISHER	6	23	SPRITEMOVEDATA_STANDING_DOWN	OBJECTTYPE_SCRIPT, PAL_NPC_RED	ViridianCityDreamEaterFisher (sym 4e:4032)	-1
VIRIDIANCITY_YOUNGSTER	SPRITE_YOUNGSTER	17	21	SPRITEMOVEDATA_WANDER (radius 3,3)	OBJECTTYPE_SCRIPT, PAL_NPC_GREEN	ViridianCityYoungsterScript	-1

Scripts of interest

• ViridianCityFlypointCallback (maps/ViridianCity.asm:13, sym 4e:4005), hooked as callback MAPCALLBACK_NEWMAP: setflag ENGINE_FLYPOINT_VIRIDIAN / endcallback. A bot cannot Fly here until it has physically entered Viridian City once.
• ViridianCityGrampsNearGym (maps/ViridianCity.asm:34): checkevent EVENT_BLUE_IN_CINNABAR; if true, the "Are you going to battle the LEADER?" line. This is a free read-out of whether Blue has been moved into the gym - see the gate table.
• ViridianCityDreamEaterFisher (maps/ViridianCity.asm:50): checkevent EVENT_GOT_TM42_DREAM_EATER / iftrue .GotDreamEater, else writetext ... / promptbutton / verbosegiveitem TM_DREAM_EATER / iffalse .NoRoomForDreamEater / setevent EVENT_GOT_TM42_DREAM_EATER. The walkthrough never mentions this; it is a free TM on the map the walkthrough tells you to fly to.

Flags and events

constant	defined in	read/written by	meaning for a bot
ENGINE_FLYPOINT_VIRIDIAN	constants/engine_flags.asm:68	set by ViridianCityFlypointCallback	Precondition for the walkthrough's "fly back to Viridian City"
EVENT_BLUE_IN_CINNABAR	constants/event_flags.asm:1303	read by ViridianCityGrampsNearGym and ViridianPokecenter1FCooltrainerMScript; it is also CINNABARISLAND_BLUE's object event flag	While clear, Blue is standing on Cinnabar Island and has not yet moved to the gym
EVENT_GOT_TM42_DREAM_EATER	constants/event_flags.asm:223	ViridianCityDreamEaterFisher	One-time TM42

Items

item	how obtained	source (label / bg_event / hidden)	one-time flag
TM_DREAM_EATER (TM42)	Talk to VIRIDIANCITY_FISHER at (6, 23)	ViridianCityDreamEaterFisher verbosegiveitem	EVENT_GOT_TM42_DREAM_EATER

Trainers - none on the overworld map.

Wild encounters - no kanto_grass.asm or kanto_water.asm entry for VIRIDIAN_CITY. Fishing group is FISHGROUP_POND (data/maps/maps.asm:457).

MAP_VIRIDIAN_POKECENTER_1F

• Script: maps/ViridianPokecenter1F.asm
• Blocks: data/maps/blocks.asm:361 ViridianPokecenter1F_Blocks
• Header: data/maps/maps.asm:463 -> TILESET_POKECENTER, INDOOR, LANDMARK_VIRIDIAN_CITY, MUSIC_POKEMON_CENTER, phone FALSE, PALETTE_DAY, FISHGROUP_SHORE
• Dimensions: constants/map_constants.asm:429 map_const VIRIDIAN_POKECENTER_1F, 5, 4 (10x8 cells)
• Connections: none
• Respawn point: data/maps/spawn_points.asm:12 spawn VIRIDIAN_POKECENTER_1F, 5, 3

Warps (def_warp_events)

idx	x	y	destination map	dest warp
1	3	7	VIRIDIAN_CITY	5
2	4	7	VIRIDIAN_CITY	5
3	0	7	POKECENTER_2F	1

Coord events - none. BG events - none.

Object events

const	sprite	x	y	movement	type	script label	event flag
VIRIDIANPOKECENTER1F_NURSE	SPRITE_NURSE	3	1	SPRITEMOVEDATA_STANDING_DOWN	OBJECTTYPE_SCRIPT	ViridianPokecenter1FNurseScript	-1
VIRIDIANPOKECENTER1F_COOLTRAINER_M	SPRITE_COOLTRAINER_M	8	4	SPRITEMOVEDATA_WALK_LEFT_RIGHT (radius 1,0)	OBJECTTYPE_SCRIPT, PAL_NPC_RED	ViridianPokecenter1FCooltrainerMScript	-1
VIRIDIANPOKECENTER1F_COOLTRAINER_F	SPRITE_COOLTRAINER_F	5	3	SPRITEMOVEDATA_STANDING_UP	OBJECTTYPE_SCRIPT, PAL_NPC_BLUE	ViridianPokecenter1FCooltrainerFScript	-1
VIRIDIANPOKECENTER1F_BUG_CATCHER	SPRITE_BUG_CATCHER	1	6	SPRITEMOVEDATA_STANDING_RIGHT	OBJECTTYPE_SCRIPT, PAL_NPC_GREEN	ViridianPokecenter1FBugCatcherScript	-1

Scripts of interest

• ViridianPokecenter1FNurseScript (maps/ViridianPokecenter1F.asm:12): jumpstd PokecenterNurseScript (engine/events/std_scripts.asm:54). This is the "heal at the Pokémon Center" beat, both before and after Blue.
• ViridianPokecenter1FCooltrainerMScript (maps/ViridianPokecenter1F.asm:15): another checkevent EVENT_BLUE_IN_CINNABAR read-out ("There are no GYM TRAINERS at the VIRIDIAN GYM"), which corroborates the walkthrough's "There aren't any other trainers in this gym".

MAP_VIRIDIAN_GYM

• Script: maps/ViridianGym.asm
• Blocks: maps/ViridianGym.blk (data/maps/blocks.asm:877 ViridianGym_Blocks)
• Header: data/maps/maps.asm:458 -> TILESET_TRAIN_STATION, INDOOR, LANDMARK_VIRIDIAN_CITY, MUSIC_GYM, phone TRUE, PALETTE_DAY, FISHGROUP_SHORE
• Dimensions: constants/map_constants.asm:424 map_const VIRIDIAN_GYM, 5, 9 (10x18 cells)
• Connections: none (data/maps/attributes.asm:657)
• Map events block: ViridianGym_MapEvents, sym 5f:43de

Warps (def_warp_events)

idx	x	y	destination map	dest warp
1	4	17	VIRIDIAN_CITY	1
2	5	17	VIRIDIAN_CITY	1

Coord events (def_coord_events) - none. There is no trip-wire in this gym; Blue is a pure talk-to trigger.

BG events (def_bg_events)

x	y	type	script/item
3	13	BGEVENT_READ	ViridianGymStatue (sym 5f:4047)
6	13	BGEVENT_READ	ViridianGymStatue

Object events (def_object_events)

const	sprite	x	y	movement	type	script label	event flag
VIRIDIANGYM_BLUE	SPRITE_BLUE	5	3	SPRITEMOVEDATA_STANDING_DOWN (radius 0,0)	OBJECTTYPE_SCRIPT, palette 0	ViridianGymBlueScript (sym 5f:4002)	EVENT_VIRIDIAN_GYM_BLUE
VIRIDIANGYM_GYM_GUIDE	SPRITE_GYM_GUIDE	7	13	SPRITEMOVEDATA_STANDING_DOWN	OBJECTTYPE_SCRIPT, PAL_NPC_BLUE	ViridianGymGuideScript (sym 5f:4033)	EVENT_VIRIDIAN_GYM_BLUE

Both objects carry EVENT_VIRIDIAN_GYM_BLUE as their event flag, so while that flag is set the gym is completely empty. EVENT_VIRIDIAN_GYM_BLUE is set by InitializeEventsScript at new game (engine/events/std_scripts.asm:438, the setevent on line 552) and is cleared only by CinnabarIslandBlue.

Scripts of interest

• ViridianGymBlueScript (maps/ViridianGym.asm:10, sym 5f:4002), the whole badge beat, in order:

  1. faceplayer / opentext
  2. checkflag ENGINE_EARTHBADGE / iftrue .FightDone (sym 5f:402d) - repeat visits get LeaderBlueEpilogueText only
  3. writetext LeaderBlueBeforeText / waitbutton / closetext
  4. winlosstext LeaderBlueWinText, 0 (loss text pointer 0 = use the default)
  5. loadtrainer BLUE, BLUE1 / startbattle / reloadmapafterbattle
  6. setevent EVENT_BEAT_BLUE
  7. opentext / writetext Text_ReceivedEarthBadge / playsound SFX_GET_BADGE / waitsfx
  8. setflag ENGINE_EARTHBADGE
  9. writetext LeaderBlueAfterText / waitbutton / closetext / end

  No verbosegiveitem: unlike Johto leaders, the Kanto leaders in GSC hand out no TM. The badge itself is the only reward besides money.

• ViridianGymGuideScript (maps/ViridianGym.asm:39, sym 5f:4033): checkevent EVENT_BEAT_BLUE / iftrue .ViridianGymGuideWinScript. Pure flavor, no learnmove, no items.

• ViridianGymStatue (maps/ViridianGym.asm:55, sym 5f:4047): checkflag ENGINE_EARTHBADGE / iftrue .Beaten; before the badge, jumpstd GymStatue1Script (engine/events/std_scripts.asm:638), after it gettrainername STRING_BUFFER_4, BLUE, BLUE1 then jumpstd GymStatue2Script (:646). A cheap read-back a bot can use to confirm the badge landed.

Flags and events

constant	defined in	read/written by	meaning for a bot
ENGINE_EARTHBADGE	constants/engine_flags.asm:54 (in wKantoBadges)	read by ViridianGymBlueScript and ViridianGymStatue; set by ViridianGymBlueScript	The 16th badge. Post-condition of this section
EVENT_BEAT_BLUE	constants/event_flags.asm:722	set by ViridianGymBlueScript, read by ViridianGymGuideScript	Set before the badge flag, between reloadmapafterbattle and playsound
EVENT_VIRIDIAN_GYM_BLUE	constants/event_flags.asm:1304	set by InitializeEventsScript (engine/events/std_scripts.asm:552); cleared by CinnabarIslandBlue (maps/CinnabarIsland.asm:23)	While set, both gym objects are absent. This is the real gate on the whole section
EVENT_BLUE_IN_CINNABAR	constants/event_flags.asm:1303	object flag of CINNABARISLAND_BLUE (maps/CinnabarIsland.asm:143), set by that script's disappear	Once set, Blue is gone from Cinnabar and (necessarily) present in the gym

Items - none. No item balls, no hiddenitem, no TM reward.

Trainers

const	class	id	party (data/trainers/parties.asm label)	script label	rematch/phone
BLUE / BLUE1	40 (constants/trainer_constants.asm:640)	BLUE1 (:641)	data/trainers/parties.asm:3154 BlueGroup (sym 0e:75ff), TRAINERTYPE_MOVES	ViridianGymBlueScript	none (no phone entry; the map header's phone column is TRUE but no phone_call targets him)

BlueGroup party, verbatim:

#	level	species	moves
1	56	PIDGEOT	QUICK_ATTACK, WHIRLWIND, WING_ATTACK, MIRROR_MOVE
2	54	ALAKAZAM	DISABLE, RECOVER, PSYCHIC_M, REFLECT
3	56	RHYDON	FURY_ATTACK, SANDSTORM, ROCK_SLIDE, EARTHQUAKE
4	58	GYARADOS	TWISTER, HYDRO_PUMP, RAIN_DANCE, HYPER_BEAM
5	58	EXEGGUTOR	SUNNY_DAY, LEECH_SEED, EGG_BOMB, SOLARBEAM
6	58	ARCANINE	ROAR, SWIFT, FLAMETHROWER, EXTREMESPEED

Class attributes (data/trainers/attributes.asm:383): items FULL_RESTORE, FULL_RESTORE (the AI will use two Full Restores), base reward 25, AI AI_BASIC | AI_SETUP | AI_SMART | AI_AGGRESSIVE | AI_CAUTIOUS | AI_STATUS | AI_RISKY, CONTEXT_USE | SWITCH_SOMETIMES. Payout 4 x 25 x 58 = 5800, matching the FAQ. BLUE is listed in KantoGymLeaders (data/trainers/leaders.asm:31), which is what selects the gym-leader battle/victory music and awards HAPPINESS_GYMBATTLE.

Walkthrough claims worth flagging against the party data: Pidgeot's flying move is WING_ATTACK, not Air Slash (which does not exist in Gen 2); Exeggutor's moves are SUNNY_DAY, LEECH_SEED, EGG_BOMB, SOLARBEAM, so it has neither Psychic nor Hypnosis; Arcanine's switch move is ROAR, Pidgeot's is WHIRLWIND.

Wild encounters - none (indoor map).

3. Blockers and gates

Gate	Enforced by (file:label)	Requirement	Unlock condition
Reaching Routes 19/20 at all	engine/events/overworld.asm:322 SurfFunction -> .TrySurf (ld de, ENGINE_FOGBADGE / call CheckBadge), and the tile-facing path engine/events/overworld.asm:469 TrySurfOW (ENGINE_FOGBADGE via CheckEngineFlag, then CheckPartyMove for SURF)	FOGBADGE + a party member knowing SURF	Both routes are open water; without Surf there is no approach
Boulders across northern Route 19	maps/Route19.asm:15 Route19ClearRocksCallback, six changeblock ..., $7a under checkevent EVENT_CINNABAR_ROCKS_CLEARED; block $7a is WALL on all four quadrants (data/tilesets/kanto_collision.asm:123)	EVENT_CINNABAR_ROCKS_CLEARED	Set unconditionally by maps/Route20.asm:12 Route20ClearRocksCallback on MAPCALLBACK_NEWMAP, i.e. by setting foot on Route 20
Blue is not in the Viridian Gym	Object event flag EVENT_VIRIDIAN_GYM_BLUE on both maps/ViridianGym.asm:183-184 objects; set at new game by engine/events/std_scripts.asm:552 inside InitializeEventsScript	Flag must be clear	maps/CinnabarIsland.asm:14 CinnabarIslandBlue: talk to Blue on Cinnabar Island; the script runs disappear CINNABARISLAND_BLUE (setting EVENT_BLUE_IN_CINNABAR) then clearevent EVENT_VIRIDIAN_GYM_BLUE. This happens in an earlier section, but a bot that skipped it will find an empty gym
Flying to Viridian City	maps/ViridianCity.asm:13 ViridianCityFlypointCallback (setflag ENGINE_FLYPOINT_VIRIDIAN), plus engine/events/overworld.asm:529 FlyFunction (ld de, ENGINE_STORMBADGE) and the landmark row data/maps/flypoints.asm:19	STORMBADGE + a party member knowing FLY + Viridian visited once on foot	Walk into Viridian City once (Route 1 north, Route 2 south, or Route 22 east). Otherwise reach the gym overland
Re-fighting Blue	maps/ViridianGym.asm:13 checkflag ENGINE_EARTHBADGE / iftrue .FightDone	-	Not possible; the battle is one-shot and there is no rematch or phone entry
(Next section) Mt. Silver	maps/OaksLab.asm:26 readvar VAR_BADGES / ifequal NUM_BADGES, .OpenMtSilver -> setevent EVENT_OPENED_MT_SILVER	All 16 badges, EARTHBADGE last	Beating Blue here is what satisfies it

Note on the Route 19 approach: the officer in maps/Route19FuchsiaGate.asm never blocks a tile, and maps/Route19.asm has no coord events. There is no NPC blocker anywhere in this section - every obstacle is either terrain (changeblock) or a hidden object (EVENT_VIRIDIAN_GYM_BLUE).

4. Bot checklist

Preconditions for the whole section: ENGINE_FOGBADGE + SURF in party, EVENT_VIRIDIAN_GYM_BLUE clear, ENGINE_FLYPOINT_VIRIDIAN set (or an overland plan to Viridian).

#	Map	Target	Input intent	Precondition	Postcondition
1	MAP_ROUTE_20	anywhere on the map	enter the map (warp from Seafoam Gym warp 1 at (38, 7), or the Cinnabar Island east connection)	-	EVENT_CINNABAR_ROCKS_CLEARED set by Route20ClearRocksCallback
2	MAP_ROUTE_20	ROUTE20_SWIMMER_GIRL2 at (45, 13)	surf into her sight cone (range 3) or talk	EVENT_BEAT_SWIMMERF_LORI clear	battle Lori (2x L32 STARMIE); EVENT_BEAT_SWIMMERF_LORI set, +640
3	MAP_ROUTE_20	ROUTE20_SWIMMER_GIRL1 at (52, 8)	surf into sight (range 3) or talk	EVENT_BEAT_SWIMMERF_NICOLE clear	battle Nicole (L29 MARILL, L29 MARILL, L32 LAPRAS); flag set, +640
3b	MAP_ROUTE_20	ROUTE20_SWIMMER_GUY at (12, 13)	optional, west end, skipped by the FAQ	EVENT_BEAT_SWIMMERM_CAMERON clear	battle Cameron (L34 MARILL); flag set, +272
4	MAP_ROUTE_20 -> MAP_ROUTE_19	east map edge	surf east across the connection (offset -9)	-	now on MAP_ROUTE_19
5	MAP_ROUTE_19	ROUTE19_SWIMMER_GUY3 at (8, 23)	talk (sight 0, will not initiate)	EVENT_BEAT_SWIMMERM_TUCKER clear	battle Tucker (L30 SHELLDER, L34 CLOYSTER); flag set, +272
6	MAP_ROUTE_19	ROUTE19_SWIMMER_GUY3 again	talk	EVENT_BEAT_SWIMMERM_TUCKER set	SwimmermTuckerAfterBattleText (the "drowning" line)
7	MAP_ROUTE_19	ROUTE19_SWIMMER_GIRL at (9, 23)	talk (sight 0)	EVENT_BEAT_SWIMMERF_DAWN clear	battle Dawn (L34 SEAKING); flag set, +680
8	MAP_ROUTE_19	ROUTE19_SWIMMER_GUY2 at (11, 17)	surf north into sight (range 3) or talk	EVENT_BEAT_SWIMMERM_JEROME clear	battle Jerome (L26 SEADRA, L28 TENTACOOL, L30 TENTACRUEL, L28 GOLDEEN); flag set, +224
8b	MAP_ROUTE_19	ROUTE19_SWIMMER_GUY1 at (13, 28)	optional, south-east, not in the FAQ	EVENT_BEAT_SWIMMERM_HAROLD clear	battle Harold (L32 REMORAID, L30 SEADRA); flag set, +240
9	MAP_ROUTE_19 -> MAP_VIRIDIAN_CITY	Pokegear map -> Fly -> Viridian	use FLY	ENGINE_STORMBADGE, FLY in party, ENGINE_FLYPOINT_VIRIDIAN	player at VIRIDIAN_CITY (23, 26) (data/maps/spawn_points.asm:15)
10	MAP_VIRIDIAN_CITY	warp 5 at (23, 25)	step onto the warp	-	in MAP_VIRIDIAN_POKECENTER_1F
11	MAP_VIRIDIAN_POKECENTER_1F	VIRIDIANPOKECENTER1F_NURSE at (3, 1)	talk, accept heal	-	party healed (PokecenterNurseScript)
11b	MAP_VIRIDIAN_CITY	VIRIDIANCITY_FISHER at (6, 23)	talk (optional, not in the FAQ)	EVENT_GOT_TM42_DREAM_EATER clear, bag space	receive TM_DREAM_EATER; flag set
12	MAP_VIRIDIAN_CITY	warp 1 at (32, 7)	step onto the warp	-	in MAP_VIRIDIAN_GYM at (4, 17) / (5, 17)
13	MAP_VIRIDIAN_GYM	VIRIDIANGYM_GYM_GUIDE at (7, 13)	talk (optional)	EVENT_VIRIDIAN_GYM_BLUE clear	advice text only
14	MAP_VIRIDIAN_GYM	save	save the game (the FAQ says so explicitly)	-	-
15	MAP_VIRIDIAN_GYM	VIRIDIANGYM_BLUE at (5, 3), approach from below	talk	EVENT_VIRIDIAN_GYM_BLUE clear, ENGINE_EARTHBADGE clear	battle BLUE / BLUE1 (6 mons, L54-58, 2 Full Restores); on win EVENT_BEAT_BLUE set, ENGINE_EARTHBADGE set, +5800
16	MAP_VIRIDIAN_GYM	VIRIDIANGYM_BLUE again	talk	ENGINE_EARTHBADGE set	LeaderBlueEpilogueText ("You'd better not lose until I beat you")
17	MAP_VIRIDIAN_GYM	bg_event (3, 13) or (6, 13)	read the statue	ENGINE_EARTHBADGE set	GymStatue2Script with Blue's name - a cheap badge assertion
18	MAP_VIRIDIAN_GYM -> MAP_VIRIDIAN_CITY -> Pokecenter	warp 1/2 (4, 17) / (5, 17), then Viridian warp 5	walk, warp, heal	-	16 badges, section complete

5. Port coverage

Beat	Port file	Status
Map header, blocks, warps, coord/bg/object events for all six maps	src/import/RomExtractorGen2.lua:782 readMapEvents, :899 (map assembly)	implemented - the tables are read out of the ROM generically, so no per-map data is hand-written
MAPCALLBACK_NEWMAP / MAPCALLBACK_TILES dispatch (needed for both rock callbacks and the Viridian fly point)	src/world/gen2/World.lua:5659, :5664	implemented
changeblock (Route 19 boulders)	src/script/gen2/Vm.lua:1002 (halves x/y to block coords, calls changeBlockFn)	implemented
setevent / clearevent / checkevent, object-event hide flags	src/world/gen2/Events.lua, src/script/gen2/Vm.lua	implemented
setflag / checkflag on ENGINE_* (EARTHBADGE, FLYPOINT_VIRIDIAN)	src/script/gen2/Vm.lua:212-223, :1584	implemented
Surf field move + FOGBADGE check	src/world/gen2/FieldMoves.lua:101 (badge table), :482 (SurfFunction port)	implemented
Fly field move + STORMBADGE + flypoint gating	src/world/gen2/FieldMoves.lua:501-505	implemented
Trainer sight cones / OBJECTTYPE_TRAINER (sight 3 swimmers, sight 0 Tucker and Dawn)	src/world/gen2/Trainers.lua:98 Trainers.sees	implemented
SPRITEMOVEDATA_SPINRANDOM_FAST swimmers	src/world/gen2/Npc.lua:23, :37, :68	implemented
loadtrainer / startbattle / winlosstext / reloadmapafterbattle / endifjustbattled	src/script/gen2/Vm.lua, src/script/gen2/Opcodes.lua	implemented
Prize money, including the 4x split and Bank of Mom	src/battle/gen2/Prize.lua:82 Prize.reward, :181 (four quarters)	implemented
Gym-leader battle/victory music via GymLeaders / KantoGymLeaders	src/battle/gen2/BattleMusic.lua:15-33	implemented
Kanto badge page on the trainer card (EARTHBADGE displayed)	src/ui/gen2/TrainerCard.lua:90, :161	implemented
verbosegiveitem (TM42 in Viridian City)	src/script/gen2/Vm.lua (verbosegiveitem)	implemented
A driver that actually plays this stretch (Routes 19/20 surf trainers, Blue)	none - tests/drivers/ has gold_trainer_smoke.lua, gold_water_moves.lua, gold_map_callbacks.lua, but nothing that reaches Kanto Route 19/20 or Viridian Gym	missing
Section-specific regression coverage for EVENT_CINNABAR_ROCKS_CLEARED sequencing	not found by grep in tests/	missing

Every "implemented" row above is a generic engine capability, not a hand-port of these maps. Nothing in src/ names ROUTE_19, ROUTE_20 or VIRIDIAN_GYM (the only grep hits are src/save_convert/data/event_flags_yellow.lua, which is Gen 1 save conversion data and unrelated). So this section should work if the extractor and VM work, but it has never been exercised end to end.

6. Unresolved / verify by hand

1. The walkthrough's boulder claim contradicts the asm. "You can't go further north because you'll be blocked by those boulders south of Fuchsia City" is only true while EVENT_CINNABAR_ROCKS_CLEARED is clear. maps/Route20.asm:12 Route20ClearRocksCallback sets that event on MAPCALLBACK_NEWMAP with no condition at all, and the walkthrough routes the player through Route 20 to reach Route 19. By the time the player is standing on Route 19 the six changeblock rocks are never placed, so northern Route 19 and the Fuchsia gate at (7, 3) are open. Treat the FAQ line as stale prose, not a gate. (What is genuinely true is that the FAQ's suggested Fly is faster than swimming back.)
2. Route 19's north connection vs. the gate warp. data/maps/attributes.asm:288 declares connection north, FuchsiaCity, FUCHSIA_CITY, 0, and there is also a warp to ROUTE_19_FUCHSIA_GATE. I did not decode maps/Route19.blk to determine whether the top block row is actually walkable, so I cannot say whether the north connection is reachable or purely decorative. Verify by hand before a bot relies on either route out.
3. Two trainers the walkthrough omits. TrainerSwimmermCameron on Route 20 at (12, 13) (L34 MARILL) and TrainerSwimmermHarold on Route 19 at (13, 28) (L32 REMORAID, L30 SEADRA) both exist with sight range 3. The FAQ says "that's all the trainers" for Route 19, which is wrong. A bot surfing the full map will get pulled into both.
4. Blue's move set does not match the FAQ's strategy text. The FAQ names Air Slash (Pidgeot) and Psychic + Hypnosis (Exeggutor); data/trainers/parties.asm:3154 gives Pidgeot QUICK_ATTACK, WHIRLWIND, WING_ATTACK, MIRROR_MOVE and Exeggutor SUNNY_DAY, LEECH_SEED, EGG_BOMB, SOLARBEAM. Air Slash does not exist in Gen 2. Do not build AI expectations from the FAQ prose here.
5. The FAQ's "Blue is one of only two trainers tougher than Champion Lance" is a subjective claim with no asm counterpart; nothing in data/trainers/ ranks trainers.
6. EVENT_VIRIDIAN_GYM_BLUE is set in a prior section. The walkthrough never mentions meeting Blue on Cinnabar Island, but maps/CinnabarIsland.asm:23 is the only clearevent for that flag anywhere in the tree. If an earlier section's document does not cover CinnabarIslandBlue, this is an orphaned precondition and a bot will find an empty Viridian Gym with no in-game hint beyond ViridianCityGrampsNearGym.
7. Blue's map header sets the phone column to TRUE (data/maps/maps.asm:458, the ViridianGym row). I found no phone_call or rematch entry naming BLUE, so I believe this is inert, but I did not exhaustively read data/phone/.