Sieza is a type of sitting position in Japan. It involves bending your knees and tucking your legs under you. Your feet should point backward while your knees point forward. Yes, it’s as uncomfortable as it looks, at least at first, but it’s one of the most basic sitting positions in Japan.
You’ll need to master this sitting position when attending certain ceremonies that require you to sit on the floor. Alternatively, you can cross your legs in front of you and nobody will bat an eye. But when in Japan, try and master the sieza so you don’t stick out like a sore thumb.