How to play
- Goal
- Divide every open cell into connected four-cell regions, with exactly one circle in each region.
- How it ends
- A chart is complete when every open cell belongs to one valid region; there is no loss.
- Record
- Your first solve time is kept per chart, and the fastest verified first solve appears with its holder.
- Divide every open cell into connected four-cell regions. Every region contains exactly one moonstone circle. The dark sealed cell, when present, belongs to no region. A square of four cells is legal; regions may take any connected shape. The worked picture shows one moonstone becoming a complete four-cell constellation.
- Tap a moonstone to select its region, then tap or drag across cells to claim them. Tap one of the selected region's cells again to clear it. Tapping a cell owned by another moonstone selects that region first. Use two fingers to pan a chart that is taller than the frame.
- Undo reverses a claim or stroke. Restart clears the chart while its clock continues. A chart finishes when all open cells form valid regions; there is no loss.
Controls
| Tap / click a moonstone | Select its four-cell region |
|---|---|
| Tap / click an open cell | Claim it for the selected moonstone; tap again to clear |
| Drag across cells | Claim cells in one stroke |
| Two-finger drag | Pan a chart larger than the frame |
| Right click a cell | Clear it |
| Arrow keys | Move focus through open cells |
| Enter / Space | Select or mark the focused cell |
| [ / ] | Cycle through moonstones |
| Delete / Backspace | Clear the focused cell |
| Z | Undo the last claim or stroke |
| R | Restart with confirmation |
| Escape | Close a panel or return to the atlas |
All 180 charts are fixed, independently proved to have one answer, and distinct under square symmetries. The circle rule adds alternatives when removed. Private partition witnesses and the solver do not ship. First-solve progress and reduced motion use morass.yonmasu.v1; only an uninterrupted first session can rank publicly. No ads or analytics run inside the game.
About Yonmasu
At a moonlit cartographer's table, each circle is a moonstone waiting for a four-cell constellation. Claim the glass tiles around it until the whole mosaic is divided.
Explore 180 original charts, sixty each on 5×5, 6×6 and 7×7 grids. Every chart has exactly one independently enumerated partition and is distinct under rotation and reflection.
The clock starts when a chart opens. An uninterrupted first solve can set the public best time, shown with its holder on every atlas card and beside the clock.
