The sleeping bag is knit from the bottom up in one piece to the armholes with a centre front seam. The sleeves are added to complete the yoke. There is a front opening with 4 buttons. I’ve used contrast for the cuffs, neckband and front bands

this design could easily be knit in the round to the front opening.

You will need approx 100g of main dk and 10g of contrast plus 4 buttons