#opening-sensei
platformWebfocuschess openingsboard3Dlibrary277 variationsengineStockfishauthnone — free
Learn and practice chess openings on an interactive 3D board. Opening Sensei is a chess opening trainer with a full library of 277 named variations across 44 opening families, organized by ECO code. Step through master lines in Learn mode, drill them yourself in Practice, or play full games against Stockfish with live opening recognition in Free Play.
###What it does
Three modes built around the same library. Learn walks you through a master line on a 3D board, half-move by half-move. Practice hands you the same line and asks you to play it. Free Play drops you into a full game against Stockfish with live opening recognition naming the variation as you transpose between lines.
###Features
- 3D interactive chess board for stepping through opening lines
- 277 opening variations across 44 families — Sicilian (38), Ruy Lopez (27), King's Indian (18), Queen's Gambit Declined (13), French (14), English (14), Italian (10), Caro-Kann (9), and more
- ECO codes (e.g.
B90 Najdorf) and per-variation lesson length estimates - Learn mode — view-only walkthrough with move list, half-move counter, prev/next nav
- Practice mode — drill the moves yourself with Undo / Reset
- Free Play — full game vs Stockfish with live opening recognition; pick White / Black / Random
- Four difficulty levels: Beginner (depth 4), Intermediate (depth 8), Advanced (depth 12), Maximum (depth 18)
- Searchable opening library by name or ECO code; no sign-in required, free to use
##The three modes#
| Learn | View-only walkthrough of a master line. Move list, half-move counter, prev/next. |
| Practice | Same lines, but you play the moves. Undo & Reset for repetition. |
| Free Play | Full game vs Stockfish. Live opening recognition names the variation as you play. |