Chess Position Diagram Builder

How to use Chess Position Diagram Builder

Illustrate one chess position for a lesson, puzzle or article. Paste its FEN record, choose the viewing side and mark a few squares. Every piece uses original vector artwork, so the diagram does not depend on a chess font or a remote image service.

1. Paste one complete FEN record or select a small local FEN file.
2. Choose White or Black at the bottom, add a title and optionally highlight square names.
3. Run the tool, inspect the diagram and source-linked square evidence, then download SVG or JSON.

Good to know

• One standard 8×8 diagram, at most 64 placed pieces and eight highlighted squares. FEN is at most 160 ASCII characters plus one optional final LF/CRLF; local file at most 256 bytes. Title is at most 64 UTF-16 units; each artifact at most 100,000 UTF-8 bytes.
• Selected canonical FEN syntax only: six single-space fields, maximal empty-square runs, ordered unique KQkq rights, side-consistent rank-3/rank-6 en-passant target, counters at most 999999999 without redundant leading zeros. Chess960, PGN, EPD, comments, BOMs and multiple positions are rejected.
• This is an illustration, not a legal-position or game-history validator. Missing or extra kings, promotion counts, pawn locations, checks, castling-piece presence and actual en-passant eligibility are not judged. An accepted diagram does not establish a playable position.
• Original geometric pieces use no chess font, copied icon paths or external assets. Title and coordinates use the viewer’s sans-serif font; overlong titles shrink without stretching glyphs. Recognition, fonts and physical printing need visual review.
• All source processing stays in the tab. The selected FEN file overrides pasted FEN; its exact decoded source remains in JSON. The SVG includes position metadata, so review what you share. No game engine, live analysis, network lookup, storage or account.