Choose HIMARI or SORA when the published dimensions fit your room and you can regularly lift, air and keep the bedding dry. Compare the firmer HIMARI with the fuller SORA by personal preference, storage space and the actual local offering. Thickness alone does not determine comfort.
Details to check before choosing
Measure the usable length and width of the floor, platform or bed base, including any raised edges. Compare those measurements with the exact model and size offered for your country. Then check the folded size and weight, and choose a sheet or cover that fits the same dimensions.
After sleep, lift or stand the shikibuton so you can inspect its underside and the supporting surface. Let both release moisture. Air both faces in a ventilated place, turn the bedding over and rotate it head to foot regularly. Fold and store it only when it is dry.
Sources for this answer
Will moving it each morning be practical?
If you plan to carry bedding from a bedroom to an airing space in a Panama City apartment, walk that route first. Can doors stay open and furniture remain in use while you pass? Check the particular variant's weight and folded dimensions. Foldable bedding is not automatically comfortable to carry through a narrow corridor every morning, and a cupboard opening may be more restrictive than its empty interior.
Choose by sleeping preference too. HIMARI has a firmer feel, a 210 cm length and approximately 10 cm total thickness; SORA has fuller cushioning, a 200 cm length and approximately 12 cm thickness. Measure the usable support and selected width. If you want deep softness or have nowhere to air the piece before storage, resolve those practical questions before buying.
How do I choose between HIMARI 日葵 and SORA 宙? · How do Japanese shikibuton sizes compare with local bed sizes?