PLL — 21 خوارزمية

The home stretch

21 beats 57. Deciding which full step to learn first? PLL is the smaller mountain — only 21 cases against OLL’s 57. Front-load it.

Climb the ladder: 4 looks → 3 looks → 2 looks

You do not need all 57 OLL cases before you start using full PLL. Harris lays out an explicit path from the beginner method to one-look CFOP:

1. 4-look (beginner)

   Edge cross, then orient corners, then position corners, then position edges — four small algorithm families. This is the beginner last layer.

2. 3-look (the bridge)

   Learn just the 7 OLL cases where every edge is already flipped to orient the corners in one look, then do full PLL in one look. Cross → 7-case OLL → PLL. This is the rung most worth climbing next.

3. 2-look (CFOP)

   Full 57-case OLL in one look, then full 21-case PLL in one look. The expert last layer.

Recognition: line up first, then look

Harris’s recognition advice is an action, not a static glance: rotate U to bring as many already-solved pieces home as you can, then read what is left over. Pre-aligning makes the remaining mismatch jump out — and it is the only way to tell mirror cases (Ua vs Ub, Ja vs Jb, the four G-perms) apart reliably.

See the two you’ll use most

Watch the two most common PLLs run on a real cube. The T-perm is the single most-used case and the backbone of 2-look PLL; the Ua-perm is the classic edge 3-cycle. The top face is already one color — PLL only slides the pieces into place.

Learn it by family, not by flashcard

Harris does not present 21 loose pictures — he buckets them into seven bite-size families that share a shape and a feel. Learn one member, internalize the trigger, then derive its mirror. The families are the study plan.

Common mistakes

Finger tricks that make PLL fast

مقدمة CFOP →

Going further