What is Tridem?
Tridem is a sliding puzzle game that moves three pieces simultaneously: a solid circle, a hollow circle, and a diamond. Each piece has a marked destination square, and a single arrow command shifts all three in the same direction. The daily rule changes by weekday and modifies how the pieces respond to directional input. The site states that every grid has one optimal solution verified by its engine.
How to play Tridem
- Read the rule displayed above the board. It changes with the day of the week and determines how each piece responds to your move.
- Use keyboard arrows or WASD, or tap the four directional buttons below the board, to move all three pieces in the same action.
- Place each piece on its dotted destination square while matching or beating the par shown next to the move counter.
Why the three-piece constraint matters
Moving three pieces with one gesture forces you to align three paths at once rather than solve for a single piece. The weekday rule rotation means Monday's strategy will not work on Tuesday. The par value gives a clear target instead of a simple completion flag. The site's interface is in Japanese, though board labels appear in English.
Reading the feedback
The board permanently shows your move count, the grid's par, and your best result, which remains empty until you solve the puzzle. Four buttons handle interaction: Hint, Undo, Reset, and Answer, which reveals the solution. The site describes its daily ranking as self-declared.
Modes
Daily grid
One numbered grid per day, with a rule dictated by the weekday, a par value, and a difficulty rating in stars.
Archive
Date navigation above the board opens past days without an account. The site states it holds a two-year stock of grids that do not repeat year over year.
Tips for a tighter solve
- The par is shown before you start. Exceeding it by many moves usually means you missed the intended sequence.
- Reread the rule line before touching the arrows. Yesterday's reflex is the first move wasted today.
- Everything runs on the keyboard: arrows or WASD to move, Z to undo, R to reset, H for a hint. Undo costs less than restarting.
- Past grids are open without an account via date navigation. Use them to learn the other weekday rules without waiting.
Popular questions
Is the rule the same every day?
No. The site says it changes according to the day of the week, and the board displays the day's rule with a one-line explanation.
Can past grids be replayed?
Yes, freely. The published rules state that the complete archive can be browsed via date navigation without restriction.
Are there multiple solutions?
The site announces a unique optimal solution per grid, verified by its engine, which is reflected by the par shown on the board.