BLDTrainer
Lesson 2

Tracing the Cube

Before you can solve a cube blindfolded, you need a way to convert the scrambled state into a sequence of letters. That's tracing. Master this and the rest of BLD is just executing algorithms.

The Procedure

Tracing is a single rule applied over and over: read the sticker at the buffer, say its letter, then jump to the position that letter names. Repeat until the cycle closes.

  1. Look at the buffer.For edges, that's the sticker on top of the UF piece (Speffz letter C).
  2. Read the letter you see there in solved-cube terms — that letter is your first target. Say it out loud.
  3. Jump to that letter's home positionand read the sticker now sitting there. That's your next target.
  4. Repeat until you read a buffer letter (C or I for edges). The cycle has closed.
  5. If pieces remain unsolved, pick any of them and start a new cycle from one of its stickers — see Cycle Breaking below.

Worked Example — Edges

A short scramble whose edges form a single 4-target cycle.

Example trace
Next: read at buffer (UF)

Step 1: Read the sticker at the buffer (UF). Suppose it shows the letter B — that's your first target. Say B.

Cycle Breaking

Sometimes a cycle closes before all pieces are solved. The buffer piece reaches its home and you're “stuck.” You break into a new cycle by picking any unsolved piece and starting from one of its stickers.

  • Closure signal: you read a buffer letter (C or I for edges, A/R/U for corners).
  • New cycle: pick any unsolved piece, write down its sticker letter as a fresh target, and continue tracing from there.
  • Solved pieces never get visited and never appear in your chain.

Parity Check

Once edge tracing is done, count your total edge targets. The cube's permutation parity constrains this number — and tells you whether to apply the parity algorithm.

Odd number of edge targets → apply the parity alg between edges and corners.

Even number of edge targets → no parity, just go straight to corners.

Quick Check

You start at the buffer and read the sticker A. You jump to A and read X. You jump to X and read Q. You jump to Q and read C. How many edge targets did you say before the cycle closed?