It was on the news the other day that syphilis cases are up in Japan. Last year had the highest number on record, and this year is on track to top that. So be safe and get tested if you are worried. Amazon Japan has self-test kits for a number of STIs including syphilis, and you can get tested at your neighborhood urologist. I got tested recently, and the doc said if I am engaged in risky behaviour, I should get tested again.
Syphilis is treatable now, so you don't have to die from it like Al Capone.