Japanese submarine fleet second most modern fleet of the world according to the Dutch magazine Marineblad dated 1938 no. 2

An item referred to the Proceedings dated November 1937 reporting that the Japanese submarine fleet was excluded the Russian the most modern of the world. Not a single boat dated from before 1920 and 16 boats with a displacement of 1.400-1.900 tons were built since 1933. The 37 1st class submarines are submarine cruisers, the 30 2nd class are mainly used for coastal defence. Most of the large submarines are armed with 6-53,3cm torpedo tubes. The J5 was able ton take a plane with her.