I am currently looking for the records of my great grandfather who died during the war. The problem is that he served in the Imperial Japanese Navy and was vaguely registered as killed in Saipan. I am unable to find more detailed records anywhere else on what ship, rank or position he served in. Is there anywhere I can find more detailed records? **Edit by Otto: to remove spammy links.
If you're not fluent in Japanese you're going to have a tough time. You might inquire at forum.axishistory.com, there are plenty of Japanese historians who visit there. Good luck.
"killed in Saipan" could mean that he was shore based. The majority of Japanese combat troops were Army of course, but Saipan was an important naval base, including land-based air units (Japan had no air force, the Army and Navy each had their own air units; I believe the aircraft on Saipan were mainly Navy). There were few if any Japanese ships at Saipan, although several were sunk or damaged in the Battle of the Philippine Sea nearby. The island commander was Vice Admiral Nagumo Chuichi, commander of the Japanese carrier force from Pearl Harbor through the 1942 battles. He committed suicide towards the end of the battle for the island. Good luck in your search and welcome to the forum.
Useful info in the the response here so I'm leaving the thread visible. It's worth noting this was a spam account run from India. Its extremely unlikely this poster's great grandfather was Japanese.