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
Replacing the mattress while keeping your bed base
If you already have a bed base in your Lithuanian home, start with its usable internal dimensions. HIMARI's 210 cm length needs more space than SORA's 200 cm length. Raised edges can make a nominal size misleading. Check full support across the chosen width and whether you can lift the mattress without dismantling the room. The ability to keep the existing frame depends on that practical fit.
HIMARI's steadier medium-firm feel and SORA's fuller cushioning are different preferences, not a ranking of comfort. Both can fold into thirds, which can help with airing even when you usually keep the bed laid out. For occasional cupboard storage, compare the folded dimensions and weight with the space you actually have. A shikibuton may suit someone who values that flexibility and can inspect its underside regularly; it still requires care when used on a bed rather than directly on the floor.
How do I choose between HIMARI 日葵 and SORA 宙? · How do Japanese shikibuton sizes compare with local bed sizes?