Japan's sunk ship: How and why?

Japanese Prime Minister Zenkjo Suzuki says that he will raise the question of the accidental sinking of the Japanese freighter Nissho Maru by a US nuclear submarine at his meeting with President Reagan next month. To that end, the American government needs ot complete a full investigation as quickly as possible to ensure that the incident does not damage the vital long-range relationship between the two allies and close trading partners. Mr. Reagan's message to the Japanese leader of personal regret is a gracious first step in resolving this tragic incident.

The incident comes at a particularly sensitive time. Against a backdrop of calls in the US by organized labor and some Detroit auto executives for restraints on Japanese car imports, the US government is urging Japan to step up its defense posture. Yet the accident provides strong ammunition in Japan for the powerful antidefense and antinuclear constiltuency there.

Many questions need to be answered, including exactly why the 6,000-ton Polaris submarine George Washington was operating close to Japan's territorial waters at that time; the extent to which the submarine sought to locate survivors,and whether the search was hampered by adverse fog and rain as US officials have said; and why the US Navy waited so long before reporting the crash to Japanese authorities.

Washington's ambassador to Japan, Mike Mansfield, is correct in calling for a investigation that is "thorough" and in which "justice must be even-ha nded."