Show HN: Criboku – a daily logic puzzle based on cribbage

Criboku, a free daily logic puzzle built around cribbage scoring, launched publicly this week via a Show HN post by user SharkeyX2. The puzzle is available at criboku.com with no ads and no account needed.

The mechanic works like this: players are given a pool of cards and must fill a grid so that each row forms a valid cribbage hand whose score matches the target values shown around the grid. Some cards and scores are pre-filled as starting clues; the rest must be deduced. A new puzzle publishes every day, and difficulty increases as the week progresses, per the HN post.

The creator describes himself as a longtime member of the American Cribbage Congress and its chief programmer, and says the project grew from a desire to build a daily puzzle page for cribbage enthusiasts. For players unfamiliar with cribbage scoring, the site includes a help page with a primer, and a Hint feature that walks through the logic required to place each card.

Two technical details stand out in the HN post. First, the puzzle generation algorithm guarantees that every puzzle has exactly one valid solution reachable purely by deduction — no guessing or backtracking required. Second, the answer is never sent to the browser at all; because the uniqueness guarantee means only one arrangement satisfies all scoring and pool constraints, the solution can be verified client-side without the server ever revealing it.

There is no company or funding behind the project as described — it is a solo side project from a cribbage community insider. The site is free, carries no advertising, and requires no registration to play.