The chair on the right would make an airplane seat seem roomy by comparison. For reference, even the chair on the left was small by Western standards (and no, these aren't kid's furniture!).
About a year ago, my venerable American office chair that I bought at Costco about a decade ago blew out a caster and I had to get a new one. Unfortunately, Costco no longer carries Western furniture so I had to turn to Japanese shops. Here is the thing about most Japanese office chairs; they come in two types: too damn expensive and average in size, and too damn small. The more reasonably priced (cheaper) ones seem to be designed for people the size of a child, or a tiny, tiny Japanese woman. They are so small because of the size of the offices and homes, not because of the size of the people. The chairs aren't for comfort or ergonomics, but rather to cram as many people into small, expensive-to-rent spaces as possible.
I won't miss having to choose between chairs that cost far too much and ones that are too small for long-term comfort.