I suppose we need to deal with this. I spent quite a bit of time with Tofiga in Fiji but he never mentioned any of this to me so I have to go entirely upon his brief comment to Tom King. I generally found Tofiga to be an excellent source of information regarding the Western Pacific High Commission, its procedures and personalities. However, a Japanese plane over Tarawa in 1937 is hard to swallow.
1. There was no Japanese search for Earhart in July 1937. It wasn't until September that Putnam asked, through diplomatic channels, if he could pay for a search by the Japanese of the islands in the mandated territories. The reply came on September 17 from Isoruku Yamamoto, Vice Minister, Ministry of the Imperial Navy, saying that: "...our Imperial nation will have all of the vessels and fishing boats in the area make every possible effort to search for the remains." The Japanese later claimed that two ships searched the southern Marshall islands - the seaplane tender Kamui (often mistakenly named in Earhart books as the "Kamoi") and the survey ship Koshu. We know that in July, Kamui was enroute from Saipan to Futami in the Osawagara Islands, far, far from the Marshalls and heading west. We don't know where Koshu was but she had no aircraft.
2. It wasn't until 1940 that the Japanese had seaplane ramps or airfields anywhere in the Marshalls, so any Japanese airplane in that part of the world would have to be ship-based. I'm not sure how many carriers the Imperial Navy had in 1937, but I do know that Akagi was in drydock undergoing a refit throughout this entire period. We know of no Japanese naval vessels in or near the Marshalls anytime in 1937 other than possibly the Kamui and Koshu in late September.
3. Had the Kamui, by any chance, been so bold as to send a flying boat as far south as Tarawa it is hard to understand why there was no British diplomatic protest similar to that filed when a U.S. Navy seaplane flew over Canton Island. Tarawa was not a lonely tropical atoll. It was a major British colonial center with offices, adminstrators, a hospital, a school and a radio station. For the Japanese to come prowling around so far outside of their own neighborhood should have brought a serious diplomatic response. No such traffic appears in the official record.
4. It seems far more likely that what Tofiga saw was a scout plane launched from one of the British cruisers that were in the area from 1935 through 1939. HMS Leith, HMS Leander, HMS Wellington, and HMS Achilles all carried at least one Supermarine Walrus.