ORBITO Solver

Orbito is an abstract strategy game for two, played on a grid of any size from 1×1 up to 4x4 (original Orbito). Each turn you may move one opponent piece to an adjacent empty cell, then place one of your own, and then the whole board turns.

That last part is what makes Orbito. The board you are looking at is never the board you are reasoning about, and because a press turns each ring by one step rather than rotating the board rigidly, a rotation can carry a line you had onto a line you didn’t. First to complete a full row, column or diagonal with your own pieces wins. Fill the board without a line and the endgame presses decide it: up to five forced presses, each turning the rings one step, and the first press that produces a line wins it.

What sets this build apart is the opponent. There are no heuristics and no evaluation function anywhere in it. Every position the computer can reach is solved exactly, by retrograde tablebases generated ahead of time and cross-verified against an independent search engine, so the computer plays perfectly on 1×1 through 4×4. It knows the value of every position before it moves, and it will take a win you had abandoned.

It runs as a terminal in your browser. Every question has a default, so you can start by pressing Enter.

Features

• Play against the computer as x or o, or play both sides yourself
• Rules set per game: grid size, rotation direction (clockwise, counterclockwise or still), transfers on or off, and the endgame presses on or off
• Solve any position you type in: it prints the perfect move, how many moves keep that result, and the whole perfect game that follows
• ? asks for the best move and perfect continuation without playing it, and * plays it for you
• m values every legal move in the position: its result, its length, and the opponent’s replies
• Undo, a board redraw, and a built-in help screen
• Moves are typed in plain notation: c3 adds a piece, a1b1 c3 transfers a piece and then adds one
• Choose how the computer picks between equal moves: fully ranked, or the first move of the tablebase line