sitting with legs splayed out, bottom on the ground
A sitting posture similar to seiza but with both legs spread outward and the buttocks resting directly on the floor. Often considered a less formal or more relaxed alternative to seiza.
See also: 正座 (せいざ)
When sitting in seiza for a long time is painful, some people sit in tonbiashi.
Tonbiashi is more comfortable than seiza, but it is not often used in formal settings.
The term combines 鳶 (tonbi, 'black kite') and 足 (ashi, 'legs/feet'), likely from the resemblance of the splayed-leg posture to a bird's stance. The exact origin is uncertain.