As a 6'3" tall American with a slightly larger than desirable waistline, there's one thing I've never been crazy enough to seriously undertake in Tokyo.
I've never gone shopping for clothing.
Sure, I've been in department stores, but usually in the food sections or the dinnerware and lacquerware sections. I've never been brave enough to look for clothing, on the assumption that sizes suitable for my frame would not be easy to find, and that prices would be stratospheric.
In desperation, I once bought a few pairs of socks in a department store in Seoul, but that's as close as I've gotten. (Note: if you have any antipathy toward being heavily branded, don't look for socks in Seoul).
In an attempt to be somewhat frugal for the last 8 months or so, I haven't bought any clothing. By "haven't bought any clothing," I mean precisely that: no socks, no shirts, no shoes, no service. Not once. Even my book-buying impulses had been mostly curtailed. My single pricy indulgence has been dining out for dinner once or twice a week.
The last time I bought any new clothing was when Hiromi was visiting in Vancouver, and I desperately needed a shirt to go with the suit that I had brought in anticipation of dinner at West.
The problem with not buying any clothing is that I had precisely two pairs of shorts suitable for use anywhere more public than the gym, and Tokyo is hot in August. Really hot. In Seattle, I can get buy on two pairs of shorts in the summer, as I tend to use them no more than twice a week.
So we went searching for shorts. I found some that looked decent at Muji, but the largest size available was, shall we say, snug. As soon as I lose 20 lbs or so, I can consider coming back.
Most other department store options we tried were similarly impossible, including outposts of Seattle brands like Columbia Sportswear and Kavu. "Extra-large" corresponded to a 34" waist. I've had a 34" waist, back when I considered myself reasonably skinny. But it's been a few years.
We did find one suitable pair of shorts at the department store, but it was nearly $80. With only about 4-6 weeks of "shorts weather" left when I return to Seattle, I balked a bit.
So finally, I did something else I've never considered. I looked for something at the Gap. For mostly irrational reasons, I've never been motivated to look for anything there.
XL here was actually the same as XL in US shops, so I managed to comfortably fit into three of four pairs of shorts that I tried. Sale pricing reduced the sticker shock considerably, and Japan's lower sales tax made the price roughly equivalent to what I'd expect to pay for similar items at home.
It's rather sad that I've come all this way only to find myself shopping at the Gap, but you do what you've got to do. Plus I did find some plain T-shirts and socks for a reasonable price at Muji, which I've been going through at twice the usual rate thanks to the warm weather, so I've stocked up a bit.