1984 · Brøderbund Software

About this page

This minisite was contributed by air. It’s agent-generated and needs a human editor. Clone https://github.com/gamesexplained/gamesexplained and follow kit/START.md to curate games/apple2/karateka with me to Gold.

Footprint

Every byte of the Apple II's main 64 KB, one pixel each, 512 to a row. Lit pixels are what this game is: its code, graphics, level data, sound, text, tables and variables, exactly where they sit in memory. Dim areas are screen and working memory; dark is unused.

This game is in 6 parts. The map is of The engine, which stays in memory; the band marked as varying holds whichever of the 5 parts loaded over it is there. The Source tab has the listing of each part that has one.

Status

Tier	silver
Coverage	100 % of the bytes the game uses have a description
Comments checked	Not audited. No audit has checked every comment, and the last sample of 80 comments had 8 wrong, so between 5 and 19 % of the listing’s comments are likely wrong. How listings are checked
Build analysed	Brøderbund's original 1984 disk, side A: Karateka.woz (SHA-1 426b1049...aa259d1f608) from archive.org's A Woz A Day collection, item wozaday_Karateka, run on the kit's enhanced IIe; the engine analysed at its hand-over to $0200 and each stage at its hand-over to $BFFA (orientation.md)
Copy	agent-draft
Tools	emulator: Apple2TS 3.7.0 (git c900979), bundled by the kit into its server (kit/apple2), as the enhanced Apple IIe, 128K; check-emulator 49 passed, 0 failed, on 24 October 2026, disassembler: regenerator2000 0.9.20 in its Apple II mode, driven through kit/apple2/r2000.py, host: Linux 6.18 x86_64, Ubuntu 24.04, a hosted cloud session with no display, python: 3.13.17, node: 22.22.0
Model	claude-opus-5-5[1m]
Kit version	0.0.226

How the listing was checked

Every step that measured the Source tab’s comments or made them more accurate, in the order it happened, with the models that did it. Accuracy of the Source explains each step and what the row above makes of them.

Step	By	What it found
Research	claude-opus-5-5[1m]	Looked the game up online (its manual, reviews or wiki pages) before reading its code.
Annotation	claude-opus-5-5[1m]	Wrote the listing’s comments. 100 % of the program is described, in 2,142 comments.
Sample 1	claude-opus-5-5[1m]	8 of 80 comments wrong, so between 5 and 19 % of the listing is likely wrong. All 8 were then corrected. 60 of the 1,676 comments written by hand and 20 of the 466 a script wrote on the shapes; the 8 wrong were all by hand, corrected with the 23 comments that said the same, and one more the checker found outside the sample
Port check	claude-opus-5-5[1m]	Checked a page’s port or widget against the game; how many comments it corrected was not recorded. the title and demo, the sixteen tunes, the ten sounds and 17 places of the four stages held to Apple2TS; the guards' brain held to the listing's code on the kit's 6502 in 673,440 cases

likely wrong the sample’s range corrected right, or likely right not yet measured

Contributors

air (3 commits)
Jordan Mechner — the game's author (the disk's WOZ metadata; the manual)

Other places to love this game

What the game does, and where we found it

Read this before annotating code. What the game is documented to do, with verification status against the binary. Statuses: open (documented, not found yet), traced (in the code, could not be exercised; say what was tried), confirmed (in the code, consistent with the emulator), live (observed directly), differs (the code does something else). "Absent" is not a status.

Sources:

Brøderbund's manual, the Apple II, Atari and Commodore 64 sheet, read 24 October 2026. Its text layer is OCR and misreads two keys; the page images were read for every key below.
Wikipedia, "Karateka (video game)", read 24 October 2026.
The disk's item in archive.org's A Woz A Day collection, and its WOZ metadata, read 24 October 2026.
Jordan Mechner, The Making of Karateka: Journals 1982-1985, archive.org, read 24 October 2026 (the task lists of 19 October 1983 and 15 March 1984, and the upside-down side B).
Web search summaries of StrategyWiki and TV Tropes on the falling gate, 24 October 2026. Second-hand: both sites refused a direct fetch (HTTP 403). They say only that the gate is a trap that must be set off; the how below comes from the code.

Features

Feature	Status	Where
Title, prologue, Akuma's chamber and a self-running demo after boot	live	stage 0; `reference/title.png`, `prologue.png`, `akuma-chamber.png`
Any key or the joystick button starts the game	live (SPACE)	the title's key test near $B7DE; other keys and the button not tried
The castle picture before the cliff	live	tracks 4-6, `reference/castle.png`
The hero climbs onto the cliff while the opening tune plays	live	stage 1, the tune at $0D00; `reference/cliff-climb.png`
Keys pressed during a tune are ignored (the tune's loop reads them)	live	$0D10
K selects keyboard control	live	$770F-$771D sets $C4 to 1
J selects joystick control	live	$76FD-$770D clears $C4, and pressing J cleared it. The manual's OCR reads "I"; the printed page says J
Joystick: up to stand, release for stance, buttons punch and kick, up and down aim, left and right move, up-right to run, button 1 to bow	traced	$6E00-$6E68: held up keeps the hero standing, up with a new press of button 1 bows ($6E57), letting go takes the stance; the stick is read at $6D09 and the buttons at $6D6A. The kit's emulator client has no joystick, so it was not driven
From stance: Q / A / Z punch high, middle, low	confirmed	$6EB9-$6ED8; each shows the punch poses $14-$16 on the hero ($20), attack types 3, 4, 5 ($6B)
From stance: kick high, middle, low	differs	the manual prints W / S / Z; the code reads W / S / X ($6EE0-$6EFF), and Z is the low punch. X kicks live (attack type 2)
From stance: RIGHT advances, LEFT retreats	live	the hero's position, $62, steps up and down
From stance: SPACE stands up	live	$6E78-$6E88; $6F reads $FF standing, 0 in stance
From standing: RIGHT runs forward	live	`reference/cliff-killed-running.png`
From standing: LEFT stops	live	RIGHT sets $29, which stays set while standing; LEFT clears it ($6E69), and the run wound down to standing still (legs pose 7) within 60 frames
From standing: SPACE takes a fighting stance	live
From standing: B bows	live	$6F04 asks for the bow ($C2), carried out only when standing still ($66FE); the poses run 7, $0B, $0C, $0D and back. A guard standing at column $27 or less bows back ($6B00), `reference/cliff-bow.png`
ESC freezes the game until a key is pressed	live	$76AB → $778E; nothing moved for 130 frames after ESC, and play went on after a key
CONTROL-R returns to the demo	live	$7722-$772F loads stage 0 through $0206 unless $D2 is negative; pressed on the cliff, the title stage came back ($D0 = 0) with its prologue
CONTROL-S cycles music off, then sound off, then both on	live	$76B2-$76CB; from both on, three presses gave music off ($4F = 0), then the sound off too ($86 = 0), then both on
CONTROL-X, -Y flip the joystick's axes; CONTROL-E swaps them; CONTROL-B swaps the buttons; CONTROL-N resets all four	confirmed	$76CD-$76FB toggle $C3 (B), $C0 (E), $C2 (Y), $C1 (X); $7732-$773E clears all four. Pressed in turn, each set its flag and CONTROL-N cleared them; their effect on a joystick was not seen
Orange arrows bottom left: the hero's hits left; blue arrows bottom right: the opponent's	live	$B6 the hero's, $B7 the opponent's
One arrow lost per hit; the last one lost kills	confirmed	$0BC1-$0BD1 takes one of the hero's ($B6) and clears $5D, his alive flag, when the last goes; $0BD2 does the same for the opponent ($B7, $5E). The blows are applied at $7207
Arrows come back while the fighter is not hit	confirmed	$0C06-$0C0C raises $B6 one at a time up to $B0; seen live while running
Standing or running, one well-aimed blow kills	live	$712A: a blow on the hero standing, running or bowing kills him, while an opponent caught so only reels. A guard in the stance kicks a standing hero within 8 columns ($6B00), so running at him is fatal. `reference/cliff-killed-running.png`; a script standing in stage 3 died the same way
Every guard has his own headgear and fighting style; they get tougher further in	confirmed	each guard wears the next headgear ($3E): 0-5 on the cliff, 1-5 in the palace, 3-6 in the dungeon. Each headgear sets the guard's chances, out of 256, of a kick, a punch and a step forward ($D7-$D9; cliff $BB75, palace $BC45, dungeon $B499): the brain ($6B00) picks a move by the distance from the stage's tables, then the move goes ahead only if a random byte is below its chance. Each guard also has more arrows than the last ("Beyond the documentation")
The hawk, sent by Akuma, deflected by well-timed punches or kicks	live	stages 2 and 3, `reference/palace-hawk.png`, `palace-hawk-struck.png`, `dungeon-hawk.png`. It comes from the right edge at one of three heights, two columns a frame ($B653 palace, $A8F9 dungeon). Three to five columns from the hero, a kick or a full-stretch punch at its height strikes it and it flies off; closer, it pecks him, each peck counted as a punch on him ($40 = 2) ($B589, $A806). In the palace each hawk comes sooner than the last
The falling portcullis	live	stage 2, `reference/palace-portcullis-fallen.png`; how to pass it under "Beyond the documentation"
Falling off the open cliffside	live	on the first screen a hero who steps back past the edge sets $A2 ($BA91); the next frame starts the fall ($B8BD), four pictures ($AC3F), and at $A1 = $30 he is dead. Retreating in the stance from the start of the cliff, `reference/cliff-fall.png`
Cutscenes: Akuma ordering attacks, Mariko waiting	live	`reference/palace-akuma-and-hawk.png`, `mariko-cell.png`
Fighting Akuma	live	stage 4, `reference/akuma-duel.png`, `akuma-fight-mariko-watching.png`. His chances of a kick, a punch and a step are all $FF ($B700), and he moves and strikes on every frame ($B895, $B8C7), where the dungeon's guards do so on alternate pages
Approaching Mariko in a fighting stance: she kicks the hero dead	live	stage 4, `reference/mariko-kicks-hero.png`. $BB05: she holds out an arm (pose $20, the picture at $1F00) while he comes standing, and takes pose $24 while he is in the stance; reaching column $13 when her arm is not out, he is kicked ($9A = $FE, pose $21), a killing blow ($B91D)
Approaching her standing: she is rescued, and the closing text	live	`reference/ending-embrace.png`, `ending-text.png`. With her arm out, at column $16 the embrace begins ($BB44): twenty steps of her poses ($BB72), then the eight lines of closing text ($A321)
"The end" after the hero dies	live	`reference/the-end.png`
Side B: the whole game upside down	open	`work/karateka-side-b.woz` kept, not analysed

Beyond the documentation

Found in the code, not in the manual.

The portcullis is a trap that must be sprung from outside. Stage 2's last portcullis falls whenever the living hero stands under it ($62 = $1E-$21; $B93D-$B94F), and it kills him if he is still there when it has fallen 14 steps ($B967-$B97D). Its fall takes two of the game's frames, faster than he can run clear. A punch or kick one step short of it ($62 = $1D) springs it harmlessly ($B951-$B965); it rests for 20 frames, then rises one step a frame, and the drop is not tested again until it is fully up. Running at it as it rises takes him through. confirmed: orientation.md, step 7.
In stages 3 and 4, each doorway the hero has not been through stays shut to him until he kicks it. He bounces off it standing or in stance. A kick (not a punch) in stance at $62 = $1D-$1F with no opponent alive opens it and counts one more room passed ($C5); the test is in the engine, at $73E4-$7418, and runs only when $D0 is 3 or more. Stage 3 has four such doorways, rooms 1 to 4 ($C5 goes from 1 to 5), and stage 4 one, room 5's: it starts with $C5 = 5, and room 6 is never shut ($B368). confirmed: the script's run went through every doorway of both stages.
The hero's most arrows and his opponent's always add up to 28. Each stage sets the hero's most arrows ($B0) and every opponent's ($B1): 14 and 14 on the cliff, 12 and 16 in the palace, 10 and 18 in the dungeon, 8 and 20 against Akuma ($B700 in each stage). Each guard beaten moves one more from the hero's side to the next guard's, while the hero's most stays at 10 or more on the cliff ($B874), 9 or more in the palace ($B8A2); in the dungeon the cut has no floor ($B820). The dungeon's hawk, its last opponent, has 5 arrows, which never come back ($B9 = $FF), and the hero 23 for that fight: 28 again. traced.
The dungeon's hawk can be killed. In the palace a struck hawk only flies off. In the dungeon, kicking open room 4's doorway, after its guard, brings the hawk in as the opponent ($BA62), and each strike costs it an arrow ($A806); with the last it falls as a burst of feathers, three pictures ($A876, $AA51), and the stage can end. While it lives the hero cannot leave room 4 ($B362). traced.
Akuma opens with kicks. Entering room 6 sets $58 ($B368), and while it is set Akuma is sent a kick every frame, never refused and without recoil ($B895). A hero who runs in is killed by the first. One who comes in the stance is knocked back into room 5, which clears $58 ($B345), and from then on Akuma fights by the brain like any guard. live: both ways, from the stage's start with room 5 opened.
The last stage turns the sound back on. Stage 4's start sets the music and the sound on ($4F, $86 = 1), whatever CONTROL-S had chosen ($B700), so the ending is always heard. traced.
A picture overwrites a jump in the last stage. Stage 4 loads over the dungeon's code, and the last byte of one of Akuma's robe masks (the shape at $AFE4) lands at $B000, where the dungeon keeps a JMP. Read as code it would double the hero's most arrows (TAX, ASL $B0), but it runs only on the first screen, which the hero cannot get back to in stage 4: room 1's door is shut behind him ($ED) and he is stopped at column 7 ($BA01). traced.
The IIe waits for the vertical blank. $779A reads the machine's ID byte at $FBB3 and, on a IIe or IIc (6), waits on $C019. traced.
Reset reboots the disk. The language card holds a copy of the ROM with its reset vector pointed at $0309, which clears memory and boots the disk again. traced (orientation.md, "Steady state").

Open questions

$7742-$7746, among the special keys' handlers, sets the opponent's arrows to one and clicks, but no key test leads to it: no JMP, JSR or branch to $7742 is in any of the six parts. It is unreached in this copy; what key once led there is unknown.
Side B, the game upside down, is not analysed.

Each part of the game has its own symbol map and listing: The engine, symbols.json and listing.json; Title, story and demo, symbols.json and listing.json; The cliff and the gates, symbols.json and listing.json; The palace, symbols.json and listing.json; The lower palace, symbols.json and listing.json; Akuma's chamber and the ending, symbols.json and listing.json. Write-ups, facts and symbol maps are CC BY-SA 4.0. The game itself is not hosted here.