The military liaison officer at the Dutch embassy at Japan supplied in his letter dated Tokyo, Japan 1 February 1922 to the supreme command of the Dutch army a lot of details dealing with the Japanese navy. The attachments were in English and not translated by him to prevent a wrong translation of the technical details. He noted that especially dealing with submarines all information were kept secret ant that hardly was possible to obtain any details.
Laid down around the end of March 1921, launched on 3 December 1921 at Kawasaki, Japan. Nothing was known about this type of submarine except that it was not a Fiat-Laurenti type earlier built at this shipyard.
Source
Archive Dutch Naval Staff 1886-1942 inventory number 137 (National Archive at The Hague, Netherlands.
Laid down around the end of March 1921, launched on 3 December 1921 at Kawasaki, Japan. Nothing was known about this type of submarine except that it was not a Fiat-Laurenti type earlier built at this shipyard.
Source
Archive Dutch Naval Staff 1886-1942 inventory number 137 (National Archive at The Hague, Netherlands.
