{"slug": "show-hn-unicornfork-a-chess-ai-that-is-fact-checked-by-stockfish", "title": "Show HN: UnicornFork a Chess AI That Is Fact Checked by Stockfish", "summary": "A developer released UnicornFork, a chess coaching tool that pairs a language model's plain-language move explanations with Stockfish, the engine used to verify the best move. UnicornFork lets users ask about any position and see the answer highlighted on the board, with built-in coaching prompts that control answer depth, jargon level and length, demonstrated on Morphy's Opera Game from Paris in 1858. The tool's pitch is that Stockfish finds the best move while UnicornFork explains the reasoning behind it.", "body_md": "AI chess coach · Backed by Stockfish\n\n# Understand the *why* behind every move.\n\n**Stockfish finds the best move. UnicornFork explains it.**\n              Ask about any position in plain language and get answers you can see on the board.\n            \n\nMeet UnicornFork\n\n## Stockfish's moves, explained in 30 seconds.\n\nSee it in action\n\n## Ask about a move. See the answer on the board.\n\nMorphy's Opera Game, Paris 1858. Hover or click the moves in the chat to see them on the board, or step through the game.\n\nMistake Blunder\n\nCoaching prompts\n\n## Make the coach your own.\n\n**A prompt decides how the coach works for you:** how deep it goes, how much jargon it uses,\n            how long its answers are. Here's the question from the game above with each built-in prompt.\n          \n\nWhat's the best move here? Morphy's Opera Game, after 15...Nxd7\n\n**16.Qb8+!!** wins on the spot: a queen sacrifice that mates in two, 16.Qb8+ Nxb8 17.Rd8#.\n\n- \n**The knight on d7 is Black's only defender.** It blocks the d-file and is the only\n                    piece that can take on b8. Taking the queen pulls it off the file, and the rook comes to d8.\n- \n**The king has nowhere to go.** The bishop on g5 covers e7 and protects d8, while\n                    Black's own bishop on f8 and pawn on f7 take the other squares.\n\nOther moves give Black time. 16.Qb5, pinning the knight, even throws the win away: after 16...Be7 17.Bxe7 Kxe7 the bishop on g5 is gone, and it's a draw.\n\n**White has something crushing here. Can you find it yourself?**\n\n- Look at Black's knight on d7. What is it doing for Black right now? It has more than one job.\n- Now look at White's rook on the d-file. Which square would it love to reach, if only the knight weren't in the way?\n- Is there a check that forces the knight to leave its post, even if it costs you something big?\n\nGive it a try: which move would you play?\n\n**White can win right away by giving up the queen!**\n\n- \n**16.Qb8+** puts Black's king in check. The only way out is to take the queen with the\n                    knight: 16...Nxb8.\n- \n                    But that knight was standing in the way of White's rook on the d-file (the column the rook is on).\n                    Now **17.Rd8** is checkmate: the rook attacks the king, the bishop on g5 protects the\n                    rook, and the king has no square to run to.\n\n                  This trick is called a **deflection**: you lure a defender away from the job it was\n                  doing. When one enemy piece guards something important all on its own, look for a way to pull it away.\n                \n\nNone of them quite right for you? Copy one and change it, write your own from scratch, or pick one other players share.", "url": "https://wpnews.pro/news/show-hn-unicornfork-a-chess-ai-that-is-fact-checked-by-stockfish", "canonical_source": "https://www.unicornfork.com/", "published_at": "2026-10-26 19:11:31+00:00", "updated_at": "2026-10-26 19:41:31.491305+00:00", "lang": "en", "topics": ["artificial-intelligence", "ai-products", "ai-tools", "large-language-models"], "entities": ["UnicornFork", "Stockfish", "Morphy's Opera Game"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/show-hn-unicornfork-a-chess-ai-that-is-fact-checked-by-stockfish", "markdown": "https://wpnews.pro/news/show-hn-unicornfork-a-chess-ai-that-is-fact-checked-by-stockfish.md", "text": "https://wpnews.pro/news/show-hn-unicornfork-a-chess-ai-that-is-fact-checked-by-stockfish.txt", "jsonld": "https://wpnews.pro/news/show-hn-unicornfork-a-chess-ai-that-is-fact-checked-by-stockfish.jsonld"}}