Then I stayed with Fanw for two months, and went through less than one bar of what I was told was Yardley's. Fanw suggested that it's a solid bar of soap, rather than a wannabe aerogel of soap and air bubbles.
Bee and Flower, courtesy of my last roommates, also seemed to hold up. Likewise whatever Japanese brand of soap I purchased here; I'm still on my first bar after 9 weeks, including a lot of two-shower days because of humidity.
(The place did provide its own soap, but as body wash, which I loathe.)
See the DW comments at https://mindstalk.dreamwidth.org/533438.html#comments