I first heard the phrase in the 1990s when I lived in Silicon Valley working for a software company.
https://www.npr.org/sections/codeswitch/2014/11/02/360479744... gives a rather comprehensive treatment. I'll provide only a cursory set of quotes:
It mentions a 1990s characterization "Basically a somewhat sexist synonym for 'open the books,'", another characterization as "kind of creepy" then goes on to expand:
> The idea of a corporation wearing clothes is kind of creepy, because the idea that corporations are people is creepy — as is the idea that showing skin equates somehow with sharing information. ...
> Greenhouse calls it "somewhat sexist" — and there's probably a reason it's "open the kimono" and not "drop the trousers" — but a kimono is technically a unisex garment. That doesn't mean the phrase isn't read in a gendered way.
> ... So there is certainly a gendered dimension to the kimono in the West. But is "open the kimono" a racist phrase, exactly? Well, it can certainly lead to, shall we say, racist-adjacent behaviors like white guys dressing up in kimonos for their marketing presentations.
> ... "It does make sense that this ethnically charged bit of jargon could have emerged from fears in the U.S. about the rise of Japan's economy in the '80s," Vanderbilt's Barry says. He adds that in his view the phrase is "kind of racist, frankly, especially if it is borne of fear of Japanese economic dominance."
> That explanation may make sense, but like most discussion on the subject, it's basically conjecture.