Thank you Ronald, I've got Kemp's Midget Sub's book in English at our local library and will check it today. And thank you again for all of your help in the past.
Yesterday I found a Pacific War bibliography on the internet. Here are the Japanese submarine and midget submarine references listed there. This information overkill is presented should someone (including myselfr) be searching the SC message database at a later date.
"Japanese I-boat Captain" by Zenji Orita with Joseph D. Carrington, Major Books, 1976. Unique cause it's by a surviving Japanese sub commander!
"Submarines of the Imperial Japanese Navy, 1904-1945" Carpenter, D. & Polmar, N. 1986. Conway Maritime Press Ltd.
"Japanese naval vesself of World War Two: as seen by US Naval Intelligence. Arms and Armour Press 1987. Interesting cause it tells what the US did know about the Japanese warships.
"The Japanese submarine Force and Workd War II" by Carl Boyd and Akihiko Yoshida. Shrewsbury: Airlife, 1996.
2 Japanese Midget sub articles and one torpedo article. All three in Warship magazine, Conway Maritime Press Ltd. and authored by Itani, J. et al.
(1993) p 113-129. "Japanese midget submarines: Kohyoteki Types A to C" (detailed account with illustrations and technical data).
(1992) "Japanese special attack weapons" pp. 170-184 (includes midget subs, human torpedoes and explosive boats).
(1991) "Japanese oxygen torpedoes and fire control systems" pp121-133