Almost no one in Japan owns a gun. Most kinds are illegal, with onerous restrictions on buying and maintaining the few that are allowed. Even the country's infamous, mafia-like Yakuza tend to forgo guns; the few exceptions tend to become big national news stories.
Japanese tourists who fire off a few rounds at the Royal Hawaiian Shooting Club would be breaking three separate laws back in Japan—one for holding a handgun, one for possessing unlicensed bullets, and another violation for firing them -- the first of which alone is punishable by one to ten years in jail. Handguns are forbidden absolutely. Small-caliber rifles have been illegal to buy, sell, or transfer since 1971. Anyone who owned a rifle before then is allowed to keep it, but their heirs are required to turn it over to the police once the owner dies.
The only guns that Japanese citizens can legally buy and use are shotguns and air rifles, and it’s not easy to do. The process is detailed in David Kopel’s landmark study on Japanese gun control, published in the 1993 Asia Pacific Law Review, still cited as current. (Kopel, no left-wing loony, is a member of the National Rifle Association and once wrote in National Review that looser gun control laws could have stopped Adolf Hitler.)
To get a gun in Japan, first, you have to attend an all-day class and pass a written test, which are held only once per month. You also must take and pass a shooting range class. Then, head over to a hospital for a mental test and drug test (Japan is unusual in that potential gun owners must affirmatively prove their mental fitness), which you’ll file with the police. Finally, pass a rigorous background check for any criminal record or association with criminal or extremist groups, and you will be the proud new owner of your shotgun or air rifle. Just don’t forget to provide police with documentation on the specific location of the gun in your home, as well as the ammo, both of which must be locked and stored separately. And remember to have the police inspect the gun once per year and to re-take the class and exam every three years.
Even the most basic framework of Japan’s approach to gun ownership is almost the polar opposite of America’s. U.S. gun law begins with the second amendment's affirmation of the “right of the people to keep and bear arms” and narrows it down from there. Japanese law, however, starts with the 1958 act stating that “No person shall possess a firearm or firearms or a sword or swords,” later adding a few exceptions. In other words, American law is designed to enshrine access to guns, while Japan starts with the premise of forbidding it. The history of that is complicated, but it's worth noting that U.S. gun law has its roots in resistance to British gun restrictions, whereas some academic literature links the Japanese law to the national campaign to forcibly disarm the samurai, which may partially explain why the 1958 mentions firearms and swords side-by-side.