Open table
A fresh deal every time you sit down.
House rules
Ivory & Ebony
Full chess against the computer: castling, en passant, promotion, check, mate and the draw rules. Every day brings a set of three mate puzzles, mate in one, two and three.
- Room
- Boards
- Game
- Chess
- Made for
- 1983
Play Ivory & Ebony
Free, no sign-up. Mouse, touch or keyboard.
How to play
- Click a piece, then its square, or drag it.
- Arrows + Enter pick up and place, X cancels.
- U undo, H hint, Q end.
- A pawn on the far row asks which piece you want.
- P to pause.
On touch
- Tap a piece, then a green dot, or drag it across.
- Undo, Hint and End sit along the bottom.
Take as long as you like. Pause any time with P; calm mode turns off every flash and shake.
Maker’s note
Chess needs no introduction, so the set is plain and the pieces are turned and drawn in code: cream ivory against dark ebony, a lit left edge on every piece. The rules are complete: castling, en passant, promotion with a choice of piece, check, checkmate, stalemate, the fifty-move rule, threefold repetition and the dead-draw cases. The computer has three levels. Easy slips now and then, medium looks a couple of moves ahead, hard looks further and does not hang its queen. Its search is counted in nodes, never in seconds, so every machine plays the same move. Ranked play is the daily set of three mate puzzles (mate in one, two and three, picked from a bank of seventy-two that were each proved by an exhaustive search), worth more as they get harder, with a small time bonus. The weekly is one game against the hard computer, and the free game lets you pick the level or play a friend on the same device (unranked). Every undo or hint costs points. Each run is stored as a list of moves and the server replays the whole thing, the computer's replies included, before it counts.
The Eracade workshop
Target scores
- 140
- 290
- 3140
- 4200
- 5260
- 6320
- 7380
- 8430
Each target is a step up. Reach the last one and you have outplayed the workshop.
In the Boards room
Board and tile games across a quiet table, one move at a time.
Your hands
Your best ten are kept in this browser with your three initials. Nothing is uploaded unless you submit a ranked hand, so clearing site data clears the list.
