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
A foldaway bed for a room used between visits
If you use a room in Croatia only for occasional stays, plan the departure morning as carefully as the first night. Folding a shikibuton can release floor space, but bedding needs to be dry before storage. An early departure from a room that will then remain closed may make that routine awkward. Consider where you could air both faces and who would finish the task if you cannot.
Measure the full supporting surface: HIMARI is 210 cm long and SORA 200 cm. Neither should be squeezed between raised edges to match a nominal bed size. HIMARI's steadier, medium-firm character and SORA's fuller cushioning offer different preferences, not a guaranteed answer for every guest. Both fold into thirds; check the folded dimensions and handling effort against your actual cupboard. A permanently arranged bed still needs regular lifting and underside checks.
How do I choose between HIMARI 日葵 and SORA 宙? · How do Japanese shikibuton sizes compare with local bed sizes?