claude (duplicate_chess)
9611c0ae0e
Local browser sandbox for "duplicate chess" — a four-player coupled-board chess variant invented by Andrew Freiberg. Scaffold per CREATE_PROJECT.md plus the approved design spec from this session's brainstorming. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
43 lines
2.3 KiB
Markdown
43 lines
2.3 KiB
Markdown
# IDEA.md — Duplicate Chess
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## What is this?
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A local, browser-based sandbox/visualizer for **"duplicate chess"** — a four-player
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chess variant invented by Andrew Freiberg (Seth's father). This project is to
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duplicate chess what the sibling `blind_chess` project is to blind chess: a
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digitization that lets an otherwise hard-to-play variant actually be played and
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studied.
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Duplicate chess: four players — North, South, East, West — and four chessboards set
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up between adjacent compass points (NW, NE, SW, SE). North and South play White;
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East and West play Black. Each player controls one colour on **two** boards (North =
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White on NW and NE; West = Black on NW and SW; and so on). Turn order is N → S → E → W.
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The defining rule: on your turn you make the **identical algebraic move on both of
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your boards**. A move is legal only if it is legal on both. When one of your pieces
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is captured on one board, its twin on your other board freezes into a **"ghost"** —
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it can never move again (no synchronized move exists for it), but it still occupies
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its square, blocks lines, can give discovered check, and can itself be captured.
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Every individual board always remains a legal game of orthodox chess.
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## Problem it solves
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In the inventor's own words, the variant can't be grasped from prose: "this is not
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really a variant that can be understood verbally after a certain point ... diagrams
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are probably essential." The physical game is fiddly to set up and play. This tool
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puts all four boards on one screen, enforces the synchronized-move coupling, renders
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ghosts, and shows *why* a move is or isn't legal — so the variant can be seen.
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## Constraints / preferences
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- Local, single-operator tool. No server, no networking, no accounts — duplicate
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chess is perfect-information, so one screen shows the whole game truthfully.
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- Stack: Vite + Svelte 5 + TypeScript, `chess.js` per board. Single package.
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- Sibling project to `blind_chess`; same homelab conventions.
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- v1 is a visualizer/sandbox. Networked four-player play and AI opponents are
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explicitly out of scope for now.
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See `docs/superpowers/specs/2026-05-19-duplicate-chess-design.md` for the full design,
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and `USERFILES/4-person-chess.txt` in the `blind_chess` repo for the original
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inventor conversation this is based on.
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