Corner to corner (C2C) crochet: blocks on the diagonal

Start and increase

1. Row 1: chain 6. Double crochet in the fourth chain from the hook and in the next 2 chains: one block.
2. Row 2: chain 6, turn. Double crochet in the fourth chain from the hook and the next 2 chains: a new block. Slip stitch into the chain-3 space of the block below, chain 3, and work 3 double crochets in the same space: two blocks.
3. Every later increase row: chain 6 and make a block on the new chain, then [slip stitch into the next chain-3 space, chain 3, 3 double crochets in the same space] across. Each row has one more block than the last.

Decrease to the corner

1. When a side reaches its full number of blocks, decrease on that edge: at the start of the row, slip stitch across the top of the last block’s 3 double crochets and into its chain-3 space instead of chaining 6.
2. At the end of a decrease row, stop in the last chain-3 space without adding a block.
3. For a rectangle, increase on one edge and decrease on the other along the longer side, then decrease on both until one block remains.

Read a C2C chart

A C2C chart is a grid; every square is one block. Rows follow the diagonals from the starting corner. Draw your picture in the chart maker and it writes every diagonal as a list of color blocks, with when to increase and decrease.

The blanket calculator turns your block size into blocks across and up for any blanket size.