Who sank the Shinonome ?
Throughout the years, there has been some discussion about the fate of the Japanese destroyer Shinonome. She was lost near Miri, Borneo in on December 17 1941. This small paper is intended to summarize the cause and circumstances surrounding the loss of the Shinonome.
The destroyer Shinonome was a powerful ship, completed in 1927 as one of the Fubuki-class fleet destroyers. At the outbreak of war in the Pacific, she was under command of Commander Sasagawa Hiroshi. His ship had been assigned to Destroyer Division 12 under Commander Ogawa Nobuki, which was initially deployed as escort for the valuable troop transports steaming towards the shore of Malaya. On December 16, Shinonome left Camranh Bay for Miri, British Borneo, together with the other two ships of DesDiv 12 (Shirakumo and Murakumo), the light cruiser Yura, the seaplanetender Kamikawa Maru, a few subchasers and two minesweepers. Also present were destroyer Sagiri of DesDiv 20, and a cover force with two heavy cruisers (Kumano and Suzuya), a light cruiser (Kinu) and the destroyer Fubuki. The invasion fleet reached Miri in the night of 15 and 16 December, where the troops went ashore almost unopposed. The 2500 men were able to capture Miri without much delay.
The next day was far less comfortable for the Japanese. Word of the invasion had reached the Dutch HQ, after which the various airfields on Borneo were put on alert. An initial attack by Glenn Martin bombers was unsuccesful, but the flying boats of GVT-7 , stationed on Tarakan on the eastern coast, did far better. Both X-33 and X-34 missed (the latter was presumably shot down by a Japanese floatplane from Kamikawa Maru), but X-32 managed to drop 5 bombs of 200 kg each, scoring two hits and a near miss on a destroyer. The latter apparently did most of the damage, as the target immediately started to list, and fires broke out aboard. A few minutes later, the waves closed over the Shinonome and her entire complement.
After the war, a committee was formed to assess the casualties the Allied naval and airforces had inflicted to the Japanese Navy and merchant navy during the war. They reached a remarkable conclusion regarding Shinonome's loss. This warship was supposedly sunk by a Dutch mine. This conclusion was taken over by two leading sources (John Dull "The Battle History of the IJN" and Jentschura/Jung/Mickel "Warships of the Imperial Japanese Navy: 1860-1945"). Dutch evidence contradicts this conclusion.
Dutch evidence regarding the attack
I recently came across a report  regarding the activities of GVT-7 (with thanks to the Dutch Naval Historical Section in Den Haag). It contains an interesting passage regarding the demise of the Shinonome:
Although the author has little doubt about the true cause of the sinking, it is interesting to see how the committee may have reached this conclusion. In 1998, an article based on Japanese records was posted on the Nihon Kaigun website, narrating the history of Destroyer Division 12 during its short career . The passage about the Shinonome mentions that the Commander of DesDiv 12, Commander Ogawa reported the Shinonome went down in a violent explosion at 0650 hours Tokyo Time on December 17 (0550 hours local or "Zulu time"). Ogawa nor anyone else had apparently observed the flying boats making their attack. He therefore concluded that the Shinonome must have been lost to a mine or induced explosion. The Assessment Committee apparently adopted this theory, and rejected other possibilities.
It is however remarkable that the Japanese authorities, in Monograph #101, do mention that Shinonome succumbed to aerial attacks. A few thoughts on why a mine was thought to be responsible:
Over the years, several myths persistently surfaced in various books around the world. Here are a few:
Comments or additional details can be sent to my e-mail.
: These flying boats were Dornier Do 24 K-1 of German origin, with X-pennants. They were armed with one 20 mm and two lighter machine gun for self defence. In addition, they were able to carry a payload of 1200 kg of bombs or depthcharges. X-32 carried six bombs, but one failed to detach itself from the rack. The Dorniers operated in small tactical units (so called GVT's) which normally consisted of three aircraft.
: This report came from "De strijd in Nederlands Oost-Indië: verrichtingen van de MLD in Nederlands Oost Indië gedurende de Japanse opmars", compiled by the Bureau Maritieme Historie in The Hague in 1962. This agency was so kind to send a photocopy. An attempt to obtain the original aviator's report proved unsuccessful.
: The small torpedoboat was the minesweeper W.7 with the merchant ship Hiyoshi Maru. The "large cruiser" Shinonome had escorted these ships to this landing site north of Miri, near Seria. Hiyoshi Maru sustained minor damage in the attack made by X-33 around 0700 hours (which apparently is Tokyo Time).
: This article was written by Allyn Nevitt: "Fleeting Glory: The Fubukis of DesDiv 12". From this article, it becomes clear that Mr. Nevitt did not have opportunity to study information from Dutch sources.
: Several sources (C.C.Küpfer "Onze vliegers in Indië" and P.C. Boer "De luchtstrijd om Borneo") mention that the attack was made from an altitude of some 4500 metres. Hitting a moving target from this height is an example of excellent marksmanship !
Thanks to Bert Kossen, Allan Alsleben and Luca Ruffato for providing additional details