Tool-assisted game movies
When human skills are just not enough

Submission #2860: p4wn3r's SGB Pocket Monsters Green "Doko Kashira Door" in 04:24.37

Console: Super Game Boy
Game name: Pocket Monsters Green
Game version: JPN v1.0
ROM filename: Pocket Monsters - Green Version (J)(V1.0)[S].sgb
Branch: Doko Kashira Door
Emulator: (unknown)
Movie length: 04:24.37
FrameCount: 15862
Re-record count: 4400
Author's real name: Felipe Lopes de Freitas
Author's nickname: p4wn3r
Submitter: p4wn3r
Submitted at: 2010-10-06 22:32:15
Text last edited at: 2011-11-06 23:52:48
Text last edited by: Ilari
Download: Download (836 bytes)
Status: published
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Author's comments and explanations:
Flygon's Point encode Mister Epic's HQx frame blended encode

Emulator: VBA-rr v20, it doesn't sync on any other version

Well, I was bored and decided to improve the published movie by 10 frames.

The rival battle could've been faster. In fact, when I started the run, I improved it, but getting to Viridian in less frames got me terrible randomness. I need to encounter a Lv2 Pidgey to do the glitch optimally and the way the RNG works, I couldn't get it without a massive loss of frames in that occasion. So, I left the battle untouched and improved the movie after it.

For those who are not familiar, Doko Kashira Door is one of the many Select button bugs that occur in the first japanese versions released, and is the fastest known way to complete the game apart from save data corruption.

I had to use v20 because it's the only version that emulates the glitch. This is unfortunate, because it doesn't have Lua scripting implemented, which could be used to shave more frames by manipulating a faster rival battle that generated good randomness for the wild pokemon encounter.

The glitch

Doko Kashira (where am I?) is a game-breaking bug on the japanese versions of Pokémon. It occurs because the programmers forgot to disable the flag for switching items or pokemon when the menu is exited in battle. This was fixed later in the (J) v1.1 release and subsequent (U) releases.

Because of this bug, it's possible to force a lot of garbage data into the game's RAM, making it go nuts. The trick abused here is to switch the 2nd item in your inventory with the first pokemon. That somehow destroys the end marker for your party and the game starts overwriting data in other portions of memory. The useful fact is that it decreases the map ID of the destination of certain doors everytime you walk four steps, this is used to get from the rival's house to Celadon and from there to the Hall of Fame.

This isn't everything about the glitch though, it may occasionally change the coordinates of a warp, change the graphics of a block of four tiles and remove their wall status, and sometimes the game may simply crash or KO your entire party.

In the run, the fight menu is clicked because it's necessary to avoid the game killing you. It's necessary to encounter a L2 Pidgey when doing the glitch. All other pokemon that appear there, except L2 Rattata, make the game crash when you take the shortest path back. Rattata's cry is longer than Pidgey's though, encountering it would make the run longer.

Mister Epic: Added YouTube module.

Flygon: Added point-based YouTube module, Mister Epic, you deserve that name, because you're friggin' epic! *hugs the epic Epic tightly* :3!

Flygon: Just some formatting related business regarding the modules, should look cleaner now.

Also, added download link for point encode, I encourage Mister Epic to upload my point upload to his Archive collection, as well as his HQ encode.

Nach: Accepting as improvement to existing run.

sgrunt: Since nobody else has apparently done a standard encode of this, I'll do so. Apparently I missed Mister Epic's encode. Either way, this will be published as soon as I grab a screenshot. Can't use Mister Epic's encode - it has a bad aspect ratio flag. I'll encode this myself as previously stated.

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