Why is every lower Cube tile blocked at the start?

Each middle-layer tile has a top-layer tile directly above it, and each base tile has tiles above it on both higher layers. Only the left and right ends of the four top rows satisfy both the uncovered and open-side rules initially.

Why is Cube rated Advanced with only 48 tiles?

The label describes geometry rather than length or player results. Cube begins with only 8 of 48 tiles free, and its two lower 4×4 squares are completely covered, so the opening has fewer structural choices than the other small boards.

Cube Mahjong Solitaire — 48-Tile Three-Layer Board

3 layers · 4×4 tile footprint · 8 tiles initially free

Coordinate-checked board

Cube at a glance

Difficulty: Advanced
Stack: 3 layers
Opening access: 8 of 48 tiles free

Opening priority

Only the eight left and right ends of the four top rows are free initially. Inspect matches among those ends and prefer pairs that shorten rows while preserving choices across the rest of the top layer.

The matching and free-tile rules are shared across layouts. See How to Play for the general rules.

Eight openings on one working level

Cube stacks three complete 4×4 squares directly above one another: 16 tiles on the base, 16 in the middle, and 16 on top. There is no inset or overhang. At the start, the middle and base contribute zero free tiles because every position is covered from above.

The top square contributes two free ends in each of its four rows. Removing a top tile is necessary to expose the position beneath it, but the newly visible lower tile can still remain side-blocked by neighbors on its own layer.

Layer-specific mistakes

Assuming the small tile count means the lower squares are available early.
Focusing on a top-row center before removing one of that row’s ends.
Expecting one removed top tile to make the tile directly below immediately free.

Cube Mahjong Solitaire