# 4D Chess: New Dimension — official product guide Also known as Fourfold; formerly TesserMate. Spatial chess for iPhone and iPad. Updated: October 14, 2026. Documented features: version 0.7. Apple's US listing confirmed version 0.7 released on October 14, 2026. Availability may differ by region. App Store: https://apps.apple.com/app/id6814281439 Website: https://tessermate.dastan.chatgpt.site/ ## What the game is Four connected boards form one chess position. X and Y identify a square within a board; Z and W identify its space. Flat 2D boards, a 3D view and a rotating 4D projection show the same position. Camera changes do not alter the rules or the game state. ## Major features - Pawnie: an optional animated chess-pawn companion with authored, built-in contextual help. On request, Gentle and Coach help levels; appearance and animation choices; hands-on setup accessible from Settings or Profile. Pawnie does not use remote AI chat and does not play your moves. - The Lost Signal: a free, optional, resumable interactive prologue with twenty chambers in four acts. Restore an observatory through real moves and linked 2D, 3D and 4D views. Beginner and experienced-player choices adjust guidance within the same story. Practice leaves saved matches unchanged. - Learning: 102 puzzles across five levels, six spatial challenges, daily streaks, foundations, a full course and movement labs. Learning progress is local to the device. - Opening previews: choose starting pieces using mini maps, then inspect the opening in 2D, 3D or 4D before starting. - Play offline against an on-device computer or take turns with a friend on one device. Offline play and learning need no app account. - Online play: private rooms, codes, QR invitations and matchmaking. Requires a connection and an app account; Apple, Google and guest sign-in are available. Compact board only, with untimed, five-minute or ten-minute clocks per player. Matching depends on another available player. - Board choices: compact 64 squares for local and online play; full army on 96 squares locally; experimental four-space 8×8 board with 256 squares locally. - Larger displays: side-by-side flat and spatial views on iPad; linked views with swappable sides on an open iPhone Duo. - Quick helper rehearses a move before commitment. Replay and basic analysis remain free. Analysis is bounded on-device search, not a guarantee of the best move or winning chances. - Saved games can sync through private iCloud when available. Study, learning progress and preferences stay on the device; Study does not sync through saved-game iCloud storage. ## Free and Fourfold Plus Core games, online play, replay, basic analysis, Quick helper, existing basic lessons, Pawnie and The Lost Signal are free. Free puzzles come as a fixed set of three. Unfinished puzzles stay available; retries within the set are free. The next set opens the following day after all three are solved. Waiting alone does not refresh the set. Free Study includes one new completed deeper review per UTC day and three new personal practice exercises per UTC ISO week. Previously sampled practice can be replayed. The first advanced Academy exercise in each module is free. Fourfold Plus is an optional monthly or yearly auto-renewing subscription. Both plans unlock unlimited access to all puzzles, Full helper with one possible opponent reply, deeper match analysis, additional reviews and personal practice within storage limits, all advanced Academy exercises, and Study notes, collections and insights. Saved Study work is retained if Plus expires. Prices and offer eligibility appear in the app. Purchase, restore and subscription management use Apple. The website does not take payments. Deleting the app or app account does not cancel an Apple subscription. ## Languages The app supports English, Ukrainian, Spanish, French, German, Brazilian Portuguese, Japanese and Simplified Chinese. Website copy is English. ## Release highlights 0.7: Pawnie, hands-on setup, The Lost Signal and clearer move guidance. 0.6: opening previews and clearer spatial board presentation. 0.5: 102 puzzles, five learning levels, six spatial challenges and daily streaks. 0.4: iPhone Duo layouts and linked views. 0.3: Fourfold Plus and local Study tools. ## Official guides - Features: https://tessermate.dastan.chatgpt.site/features/ - Pawnie and story: https://tessermate.dastan.chatgpt.site/learn/pawnie-and-lost-signal/ - Puzzles: https://tessermate.dastan.chatgpt.site/learn/puzzles/ - Free versus Plus: https://tessermate.dastan.chatgpt.site/plus/ - Release highlights: https://tessermate.dastan.chatgpt.site/whats-new/ - Support: https://tessermate.dastan.chatgpt.site/support/ - Privacy: https://tessermate.dastan.chatgpt.site/privacy/ - Structured product facts: https://tessermate.dastan.chatgpt.site/site-facts.json ## Support and contributions Email: TesserMate@proton.me Community contributions prepare an email draft for the user to review and send. There is no public posting API or automatic publication. Editorial review and permission are required before publication. ## Gameplay films Short, silent web editions of October 2026 app captures. Some interface details differ from the current release. - [One position. A whole new perspective.](https://tessermate.dastan.chatgpt.site/watch/four-dimensional-board/): The title asks, “How many pawns?” A chess opening rotates in the 4D view. Boards and pawns appear nearer and farther away as the projection turns. Eight pawns remain in the same position throughout; only the view changes. - [One move. Another dimension.](https://tessermate.dastan.chatgpt.site/watch/mate-in-one/): “Mate in one. Which dot?” appears above a rotating position with the queen’s legal targets lit. The video cuts to flat boards. A highlighted destination is chosen; the app reports checkmate and shows its result. The final view returns to the spatial board with a line from queen to king. The caption reads, “Two more dots also mate.” - [A familiar jump. New places to land.](https://tessermate.dastan.chatgpt.site/watch/knight-moves/): The title asks, “One knight. How many moves?” A selected knight and its legal destinations remain highlighted while the four connected boards rotate in the projection. The position has six legal knight targets. No piece is moved in this clip.