Stockfish 18
Every game in Casteria is played against Stockfish 18, shipped unmodified.
Opponent strength
Every opponent plays at a set strength from 1 to 2,700, shown before you play. Weak opponents make beginner mistakes: at strength 250, about half their moves are random.
| Strength | Random moves |
|---|---|
| 250 | ~50% |
| 400 | ~40% |
| 600 | ~29% |
| 750 | ~21% |
Six difficulty settings
The setting decides how strong every opponent is and how deep the puzzles go. Grandmaster unlocks when you finish the game; Regicide unlocks when you finish everything.
| Setting | Strength range |
|---|---|
| PawnlingYou have never played chess. | 1 – 400 |
| SquireThe normal way to play. | 100 – 1,000 |
| AdeptStronger opponents, deeper puzzles. | 300 – 1,400 |
| MasterNo easy opponents anywhere. | 550 – 1,800 |
| GrandmasterUnlocked by finishing the game once. | 1,300 – 2,000 |
| RegicideUnlocked by finishing everything. | 2,000 – 2,700 |
the catch puzzles
5,890 catch puzzles
Every wild piece you meet sets you a checkmate puzzle instead of a fight. The positions come from real games, and the engine has verified each one as a forced mate in the stated number of moves. Find it and the piece joins you. Two wrong moves and it runs away, and you lose nothing.
- 2,290Mate in one
- 1,600Mate in two
- 900Mate in three
- 600Mate in four
- 500Mate in five
Puzzles get deeper as you go. The first pieces you catch are all mate in one.
practice modes
Chess outside the story
The Puzzle Explorer opens the whole bank of 5,890, sorted by depth or by the name of the pattern, with or without a clock. It is practice only and never touches your save.
A daily puzzle, the same for every player, keeps a streak. The Simul Hall runs timed rushes: ten checkmates against the clock, from ten mate-in-ones in a minute up to ten mate-in-fives in nine minutes. And Chess in the Park:
Play twelve games at once at Rookwood’s festival. Each opponent moves when you reach their board. Make your move, then continue to the next board.
Chess in the Park, a simultaneous exhibitionfor beginners
The Pawnling setting is built for people who have never played chess, and its first opponents play at a strength of 1.
A short chess lesson plays before the game starts, and the title screen holds the whole course: five chapters from the names of the squares to castling, en passant and promotion. After that, the University teaches the rest in 202 lessons.
The free demo includes Openfield and Frostford. Your save carries into the full game.