How to play
- Goal
- Shade cells so the unshaded cave is one connected area, every shaded cell can reach the grid edge through shaded cells, and each number counts the unshaded cells it can see in straight lines, including itself.
- How it ends
- A chart completes when all three rules hold; marks can be changed and there is no loss state.
- Record
- The time of the first unaided solve of each fixed chart is kept locally and may rank publicly.
- Tap a free square to shade it as rock; tap again to clear it. A numbered lantern stays open and counts itself plus every consecutive open square it sees north, east, south and west until rock or the edge stops the view.
- The worked picture shows a lantern marked 1 in a separate 2×2 sample. Rock beside it stops both rays. The far corner must be rock too: left open, that corner would be disconnected from the lantern's cave.
- All open squares must join by shared sides, and every shaded square needs a shared-side rock route to the grid edge. Open notes are optional and do not change the answer. Undo restores the previous mark; Restart clears marks without resetting the clock. There is no loss. A reloaded unfinished chart stays local only, while later solves are untimed practice. Public first-solve times may be up to 24 hours.
Controls
| Tap / click a free square | Shade a rock or clear it |
|---|---|
| Mark open button | Use taps for optional open notes; tap it again to return to rock |
| Right click a square | Place or remove an optional open note |
| Arrow keys | Move focus around the chart |
| Enter / Space | Toggle rock on the focused square |
| P / Backspace | Mark the focused square open or clear it |
| U / Z | Undo the last mark |
| R / Restart | Clear marks without resetting the first clock |
| Escape | Close a panel or return to the atlas |
Every chart has one answer, independently enumerated at build time, and a separate bounded deduction trace completes each without choosing a branch. Private witnesses never ship. Saves use morass.cave.v1; sound follows the shared arcade setting. No ads or analytics run inside the game.
Watch how to play
About Cave
In the Amber Lantern Grotto, shade blue-black bedrock around a warm limestone cave. Brass lanterns count the open squares they can see in four straight directions; rock stops their light.
Shape one connected open cave while every piece of rock can reach the outer rim through rock. All 160 original charts have one independently verified answer and a deduction trace that completes them without a blind branch.
Your first finish time stays in this browser. An uninterrupted first solve can claim the named public best for its chart.
