Checker / Draughts: The Game Boy Opponent That Cannot Cheat

Checker / Draughts: A Game Boy Opponent That Literally Cannot Cheat

There's a specific kind of frustration that only a board game against a computer can produce. You make a move, the machine responds instantly with something that feels too good, and a small voice asks: is it actually playing the same game as me?

Usually you never find out. The AI is a black box, and you're left assuming it's fine, or assuming it isn't.

Checker / Draughts, our Game Boy take on English draughts, settles the question in the most satisfying way possible — by making it structurally impossible for the machine to cheat.

The rule that catches everyone

Before any of that, the rules themselves. This is standard English draughts on an 8×8 board, and it starts with the rule that has ruined more casual games than any other:

Capturing is compulsory. If any of your pieces can capture, then only captures are legal that turn. There is no quiet move offered instead. You don't get to decline, and you don't get to tidy up a different part of the board while the threat sits there.

And if the piece that just captured can capture again, it must — it stays in your hand until the chain ends, and you can't fall back and use a different piece to continue it. One piece, all the way to the end of the line.

Kings are similarly honest: a man reaching the far row is crowned and may then move one square diagonally in any direction. There are no flying kings here. No long-range swooping across the board. And if you crown part-way through a capture chain, the chain stops right there — promotion is the end of the turn, not the middle of it.

That combination is what makes draughts a real game rather than a shuffling contest, and it's the reason a machine opponent is worth having at all.

Same list, same code

So here's the answer to the fairness question, and it's the best thing about this build.

The machine doesn't just follow the same rules — it picks its moves from the same legal move list, through the same code path, that you do.

That means every rule applies to it by construction rather than by a second implementation someone wrote alongside the first. Compulsory capture. Chain continuation with the same piece. Promotion stopping the chain. If you couldn't make a move, the machine can't either. There's no separate AI ruleset to drift out of sync, and no bug in one that isn't a bug in the other.

It plays the same game you do because it is running the same game you do. After years of quietly suspecting computers of something, it's a genuinely refreshing answer.

Take your turn back

The other feature worth the price of admission: SELECT takes a turn back.

In two-player mode it undoes the last move. In one-player mode it undoes your last move — and the machine's reply goes back with it. Which is the important part. It can't simply replay the position you just rejected and hand you the same beating again; the reply is genuinely un-made, and the machine has to choose afresh.

A capture chain rewinds whole, so you're never left stranded mid-jump with half a move on the board. The last 32 turns are remembered.

It's a small thing, and it changes the game completely. You can try the move you're not sure about. You can see what you missed. For a handheld from 1989, that's an astonishing bit of quality-of-life design — and it's the feature that most made me want to keep playing.

The d-pad is rotated 45 degrees

A checker's neighbour is diagonal, which means nothing in this game moves straight sideways. So the d-pad behaves accordingly: UP and RIGHT both go up the screen, DOWN and LEFT both go down.

The cursor also walks only the squares a piece could actually use, stepping over the ones that don't matter — which spares you the fiddly business of nudging a pointer across empty ranks. Once you're carrying a piece, that's all moot: each press just cycles to the next square it can legally reach, and it wraps.

It's a thoughtful bit of interface work, and it's the kind of thing that only gets noticed when it's missing — the original Game Boy's d-pad was never designed for a board game, and this is a clean solution to a real problem.

One honest gap

There's no draw rule. Two players who only shuffle can keep going forever, and nothing will call it.

The game is upfront about it rather than pretending otherwise, and in practice you'll almost never see it. But it's worth knowing before you settle in for a marathon.

The border is the game's own artwork

The Super Game Boy border here is a proper piece of work: green baize, a checkerboard bezel around the screen, and crowned and uncrowned pieces down either side.

The lettering is the detail that gets me. It isn't a second font — the generator parses the 5×7 glyphs out of the game's own tile art, so the border reads DRAUGHTS across the top and CHECKERS across the bottom in exactly the same hand as the status row inside the screen.

On plain DMG hardware the upload is skipped and the game boots exactly as it does without it.

Under the hood

C and GBDK-2020, no engine, on a ROM-only 32 KB cartridge, with the board art generated from a Python script.

The engineering discipline here is the part I'd point at. The rules engine is a pure header with no GBDK in it at all — deliberately free of any Game Boy dependency — which means the move generator, the capture chains, promotion and the search can all be unit-tested on the host machine. It's fuzzed with random self-play before anything touches a ROM, and then the built ROM is driven headless and asserted on.

That's three layers of checking for a game about moving counters diagonally. It's exactly the right amount, and it's why the fairness claim above isn't just a nice sentence — it's the thing the tests exist to protect.

How to play it

Click the screen for keyboard focus. START begins, and SELECT on the title screen switches between 1 PLAYER and 2 PLAYERS — it boots into 1 PLAYER, so you can be playing within seconds.

A picks a piece up and A again puts it down. B puts a piece back, though it'll do nothing mid-chain, because the capture has already happened by then. On the game over screen, START or B deals a new game.

Go and lose honourably

It's free in your browser, running on the hardware it was written for, with nothing to install.

Play the machine. Then take your turn back, and play it again — because that's the feature that makes this one worth your evening, and it's the one you'll miss in every other draughts game you ever touch.

Have you beaten it? We want to know — and we want to know how many turns you rewound getting there.