With 2.5 mm / US1 needle, using Provisional cast on method and leaving a 10 cm [4"] tail for crocheting the
button loop, cast on 84 (84, 92, 92 // 100, 100, 108) sts
Row 1: Purl to end of row
I-cord edge
Make 3 sts into first st (k1, k1tbl, k1) [2 sts increased], *sl 3 sts back on left needle purlwise, k2, sl1k, k1,
psso [1 st decreased]; repeat from * to last st
Sl 3 sts back on left needle = 4 sts
Bo1, sl1k, k1, psso, pass first st over last st = 1 st
Do not break yarn
Remove provisional waste yarn, and place 84 (84, 92, 92 // 100, 100, 108) live sts onto 2.5 mm / US1 needle
= 85 (85, 93, 93 // 101, 101, 109) sts
Do not join work