"On This Date in Cryptologic History" Calendar
1943: New Zealand corvettes disable Japanese submarine and seize codebooks.
29 January 1943: Two New Zealand corvette warships - Kiwi and Moa (the smallest of their kind) rammed the Japanese submarine I-1. Gunfire was exchanged and eventually the I-1 hit a reef and was disabled near Kamimbo Bay. Seized from the submarine were approximately 200,000 JN25 codebooks which proved very valuable in that they gave the Allies advance warning of raids and other details of Japanese naval force movements.
Read the whole story via the National Archives - see link below.
Photo is from: http://www.nzhistory.net.nz
