Algorithm Notation

In general, a single letter means a quarter turn clockwise, a letter followed by an apostrophe (') means a quarter turn counterclockwise, and a letter followed by a two (2) means a half turn of the face. Middle slices act like L, F and D faces, so M is a rotation in the same direction as L and R' etc.

3x3

In addition to R, L, U, D, F and B, I'll sometimes use lowercase letters. Those are not the same as their capital counterparts. A lowercase letter means turning the outer face and the adjacent middle slice. For example r = R M' and u' = U' E.

5x5

The notation used for 5x5 cubes is just an expanded version of the 3x3 notation.

RLUDFB: outer-most layers like on the 3x3
rludfb: slices inbetween the middle slices and the outer faces
MSE: all three inner slices
mse: the slice through the center piece