In Japan, the guns subject to regulation include:
•Air Rifles – requires police lecture, certificate, letter of recommendation.
•"Hand Rifles" (essentially air pistols with a rifle stock and long barrel sleeve permanently attached to discourage concealment) – same requirements as air rifle.
•Air Pistols (limited to 500 people in the entire nation, for sports shooting only).
•Pistols (limited to 50 people in the entire nation, for sport shooting only).
•Shot guns — Requires shooting course, background check on your family, lots of police paperwork to obtain permission to purchase the gun, gun must be presented to the police for "stamping".
•.22 Caliber Rimfire Rifles – only allowed for target shooting, require long-term memberships in several gun clubs, lectures, certification of shooting skill, etc.
• Centerfire Rifles – Only bolt-actions are allowed , and only for target shooting and hunting – require ownership of a rimfire rifle first, 2 years participation in .22 shooting events (10 years for hunting purposes), mostly the same paperwork, background checks as for .22 caliber.
Buying ammo requires written permission from the police, limited to 800 rounds stored at home, 4,000 total.
If you're still interested, here's a good import/export info resource:
Export911.com