Rib pants (リブ編パンツ) TB8104
Gauge is over 10 cm with JPN 7 (4.2 mm) knitting needle.
Pattern also recommends JPN 5 (3.6 mm) knitting needle and 6/0 (3.5 mm) and 8/0 (5 mm) crochet hooks.
Yarn amount is specified by weight only. (105 g)
This is a Japanese-style graphical pattern, but it includes English translation for all terms. The drawstring requires basic crochet skills.