It is one of my comment responses today.
HealthOne is a product of Legend Travelers.
Legend Travelers, in turn, has an underwriter in Indianapolis, Indiana called HCC Medical Insurance Services. Up to about July, it was known as “Multinational Underwriters”.
HCC Medical Insurance Services is an underwriting subsidiary of HCC Insurance Holdings, Houston, Texas. New York Stock Exchange Symbol: HCC.
So your HealthOne policy is distributed in Japan, but appears to be underwritten in America.
[Update: a few screen shots for you (click to enlarge):
The first link in the chain is that HealthOne is a brand of Legend Travelers, the one that has an office in Osaka but a base in America. Legend Travelers in America can be contacted by phone at (317) 262-2132. This is in Indianapolis, Indiana. The related fax is (317) 262-2140.
These numbers were shared with a company called “Multinational Underwriters”, which subsequently changed its name to “HCC Medical Insurance Services” (same phone number) this past July. HCC Medical Insurance Services, in turn . . .
. . . is a subsidiary of HCC Insurance Holdings of Houston, Texas. (Notice the same fax number 317-262-2140.) HCC Insurance is publicly held, and the stock trades on the New York stock exchange with the symbol: HCC.
According to Google finance, HCC was up in Friday’s trading in New York: HCC quote on Nasdaq.com. ].