[First Fair Isle]
M size only: Work row 1 and row 2 once. 258 st.
Widening of sleeves and front neckline
M size: Knit row 1 and row 2 once more. 258 eyes.
This is not to fix error in the pattern.
There is no error in the pattern, but it is a correction to make it easier to understand.
BRP1 (brioche purl 1): purl stitch together with its 2 YOs .
Bicolor brioche ribs
Round 3 (CC): Drop YO from previous round, YO, *K1, Sl1yo; rep from * to end of the round.
(It is a little confusing, as Round 2 ends with YO and Round 3 starts with YO, but it is not a mistake. When working Sl1yo on Round 3, slip both the MC stitch and the YO from the previous round together, then add another YO on top of them. There will be two YOs on a stitch.)
Abbreviations and stitch guides
BRP1 (brioche purl 1): P together left needle 1 and YO2.
Sl wyf- slip stitch with thread in front
Bicolor brioche rib (2 eyes 4 laps)
Lap 3 (CC): Drop YO from the previous lap, YO, *K1, Sl1yo; Repeat from * to the end. (At the time of Sl1yo in loop 3, the loop 2 slides and the looped loop are both slid together, and the thread is put on it. As a result, the thread is looped twice on the same loop.)