CCH Level 1 Key Piece Burr Set

Purchased from Creative Craft House 2007.
(wood box 3.4" x 9.25" x 4.1" with 27 wood pieces, each 3.1" long by 3/4" square)

This set has 27 2x2x6 unit standard 6-piece burr pieces numbered from 0 to 26, where piece 0 is the solid piece. A total of 69 different level 1 standard 6-piece burrs can be selected, where all use piece 0 as a key piece, and the other 5 pieces are specified with a tic-tac-toe notation:

CCH Pieces and Sample Solutions: