i agree that the loft in all liklihood is probably used for storage. as with most japanese residential architecture there is little in the way of built storage therefore using a loft is ideal, and natually accesses via steps/ladders is typical and expected in japan anyhow.

beautifully designed and executed i think. might have been nice to punch some skylights or sim through the flowing roof form to enable sufficient daylight during the dark and cold winter months. nice to see “shakkei” (borrowed scenery) being used again (small garden near entrance) which certainly bridges the gap between made and natural. great job!