First visit to a Japanese gym almost always requires a one-time registration fee, on top of the day pass.
One of the largest and most legendary gyms in Japan, in Suginami, Tokyo.
Tip: most city gyms take cards, but carry some cash just in case.
Gyms use the traditional Kyu/Dan belt system instead of V-grades. Routes are marked with colored tape; you start around 10th–8th Kyu and work down as numbers shrink. Hitting 1st Kyu (roughly V5–V6) puts you at the doorstep of Shodan (V7–V8).
One heads-up: Japanese gym grades are famously "sandbagged" — tough for the grade. Don't sweat it if you can't climb your usual grade on day one.