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STACKING LAB · PRACTICE GUIDE

Perfect Clear practice

A Perfect Clear leaves no blocks on the board after a line clear. In Stacking Lab’s Perfect Clear Freeplay, the aim is to keep finding those opportunities across a session, rather than stop after one opening sequence.

What Freeplay trains

The dedicated coach looks for a reachable Perfect Clear using the visible pieces and hold. When it cannot find one, it tries to keep the board low and accessible for another opportunity. The PC counter beside the board records completed Perfect Clears.

A successful PC does not end this mode. The board empties and you can continue with the next pieces. That makes it useful for practising what comes after a clear as well as the first attempt.

Practise one decision at a time

  1. Start with an empty board. Open Freeplay and leave gravity off while you study the available pieces.
  2. Inspect the spaces you are leaving. Before locking a piece, ask which visible piece could fill each gap and whether it can actually reach it.
  3. Use hold deliberately. Compare spending a useful piece now with keeping it for a remaining cavity. The coach considers hold as part of its search.
  4. Review unsuccessful attempts too. If blocks remain after a clear, use undo or move history to find the placement that made the remainder difficult to fill.

After a successful clear, try to describe the sequence in terms of the gaps it solved. Recognising those shapes is more useful than memorising one set of button presses.

Freeplay or Perfect Clear Opener?

These are different exercises. Perfect Clear Opener is available under Openers for practising a defined starting pattern. Freeplay is for continuing play and seeking repeated empty boards with its own coach.

Freeplay does not guarantee a PC for every queue. The coach sees only the configured preview and has a limited search budget; an unreported solution may still exist.

Questions

Does clearing four lines always count as a PC?

No. Blocks anywhere on the board mean it is not a Perfect Clear. The PC counter increases only when a line clear empties the field.

What should I do when a PC no longer looks possible?

Keep the surface low, avoid sealing gaps and clear down. Use the next opportunity as another attempt instead of treating the session as failed.

Try it on the board

Free, ad-free and playable in your browser. No account required. A keyboard is recommended.

Start perfect clear practice