afterglow

Tap a piece, then a dotted square. You play the side shown below the board; the other side responds automatically. Standard chess rules apply, including king safety, castling, en passant and promotion.

The limit counts only your moves. A ◆ and dashed outline mark a capture target, even if it moves. A capture mission ends when that piece is taken; it does not claim that the exchange gains material.

Every move that still forces the mission is accepted. Other legal attempts stay on the board's starting square so you can try again. Undo reverses a whole turn; Reset starts this position again. Hints first suggest an idea, then a piece, then a move.

Keyboard: Tab to the board, use arrow keys to navigate, Enter or Space to select and move; Escape clears selection. All ten levels are available from the menu.

A new local-date selection rotates through 30 bundled variants. Each day's selection and completed levels are saved on this device when storage is available. Nothing is downloaded during play.

Puzzle positions: Lichess open puzzle database, released under CC0 1.0 Universal. No individual puzzle author is supplied. Level 2 variants advance the source line to its final capture; other starting positions apply the database's setup move. Explanations and interface are original.

Chess rules: chess.js 0.10.3, Jeff Hlywa, BSD 2-Clause. The full notice is below and retained in the inline code. Added internal move hooks for the exhaustive verifier.

Copyright (c) 2020, Jeff Hlywa (jhlywa@gmail.com)
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