The IJN had updated that same code circa early 1943, suspecting we may have cracked a portion of it, after their debacle at Midway. Fortune, or if you will, Divine Providence intervened when a New Zealand destroyer attacked and destroyed a Japanese submarine in the waters near Guadalcanal (by ramming it, no less!) Part of the debris that surfaced was a copy of the updated cyphers for the JN-25 code which had been previously compromised. The Allies, after this stroke of fortune, had it all....
the infowarrior
By the way: if you guys want to dig through some alternate interpretations of Canadian history, feel free. Lord know us Canucks have weighed in on your events.