brightline

Tap one of your pieces, then a dotted destination. You play the side named below the board; the defender replies automatically. These are short tactical positions, not full matches. Standard chess rules apply, including check, castling, en passant and choosing a promotion.

The move limit counts your moves only. A ◆ and dashed border mark the specific capture target. Each mission is forced against every legal defence: “Capture” means take that piece. It does not promise a material gain: the defender might recapture after the mission ends.

Every move that still forces the mission is accepted; a legal move that throws it away stays unplayed. Undo takes back a whole player/defender turn, as often as you like. Reset restarts this puzzle. Hints reveal an idea, then a piece, then a move.

Keyboard: Tab to the board, arrow keys to explore, Enter or Space to select and move, Escape to deselect. U undoes and R resets when the board has focus. Progress saves on this device when storage is available, and everything plays offline. Each UTC day selects ten positions from three curated editions (30 puzzles total); editions repeat every three days. A new day starts fresh when you open or reload the page.

Positions come from the Lichess open database puzzle export, dedicated under CC0 1.0 Universal (legal text). Individual authors are not supplied and no endorsement is implied. Each puzzle applies the source’s setup move; missions, hints, titles and explanations are written for Brightline. The source identifiers and game links for all three daily editions are listed below. Capture missions deliberately promise taking the marked piece, even if it can then be recaptured.

Rules use chess.js 0.10.3 by Jeff Hlywa, under the BSD 2-Clause license. The bundled copy exposes legal-move hooks so the page can verify positions locally; no remote engine or network request is used.

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

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.