{
  "id": 5977786,
  "title": "I asked astra to make playable 4D chess",
  "url": "https://urgent.news/2026/09/06/i-asked-astra-to-make-playable-4d-chess",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-06T11:04:07.000Z",
  "source": {
    "name": "Hacker News",
    "slug": "hacker-news",
    "url": "https://4d-chess.pages.dev/"
  },
  "original_language": "en",
  "account": "White initiates the game by selecting a piece and a square marked on the 3D chessboard. The board is composed of layers within a layer, with each square corresponding to a square in another copy of the board. The fifth dimension, W, allows a piece to move between these copies while keeping its X, Y, and Z positions unchanged. This results in a space that appears 3D but includes a fourth dimension.\n\nIn the game, the inner cube appears smaller due to the projection onto the screen. The move notation, such as a1 [0,1], refers to the file, rank, Z, and W coordinates. For instance, a1 [0,1] is the top-left corner of the board on the second layer when looking through the inner cube. Pieces can only move within the four positions along the X and Y axes, and the Z and W axes only allow for one step in any direction.\n\nPieces block sliding moves in the traditional sense, and the king must always be protected. The game also has its own rules regarding checkmate—a king is attacked and has no legal moves to escape—and draws, which occur under specific conditions like stalemate or lack of pawn movement for 100 turns.",
  "summary": null,
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}