Blintz fold
A blintz fold is the move of folding all four corners of a square in to its center point, producing a smaller square rotated 45 degrees.
Crease both diagonals first so the center is clearly marked. Then fold each corner in turn so its tip lands exactly on the center where the creases cross, and press flat. The name comes from the way a blintz pancake is folded around its filling, and the move is a common opening for boxes and many traditional models.
Gaps or overlaps at the center are the typical problem, and they grow into crooked walls or uneven edges later. Align each tip with the crossing of the diagonals before creasing, and check the four new edges form a neat square. The Masu Box starts with a blintz fold.
