ORIGINAL: Bliztk
Well, Sunburst, cites that only a few betty formations trained for low level torpedo attacks before the war because they were used in China to long-range strategic bombing.
For example when Japanese Intelligence learned of that PoW and Repulse were at Singapore they redeployed a torpedo trained squadron (Genzan ¿?) to Saigon.
I think that the same squadron attacked the Marines at Guadalcanal on 9th August (the famous photos of Betties at mast level)
You can make far too much of the missions over China - something JNAF is very proud of ("the first transoceanic air raids in history"). And learned lessons from (unescorted = bad idea). But remember - the bombers were DESIGNED as torpedo bombers - they are not efficient as bomb type bombers - and all the training of the crews (in JNAF) was FOCUSED on things facilitating naval attack (recognition, navigation, approach tactics, etc). I don't think ANY JNAF unit fitted with torpedo bombers as such was not able to perform this mission at need - and the most I would do is make the units that did well get a better proficiency rating. But this isn't a game in which we have proper limits on torpedoes - so we need to compromise a bit. But to the degree we do that - don't think it means that these specialist aircraft with trained to suit crews really were not up to it: surely they were. This was a long term JNAF goal - and the very first long range land based bomber was destroyed - even the paper plans - so no one would be wiser. A slightly pre war version was also used over China. They had been working on this for a long time - and Adm Yamamoto was the one responsible - as head of JNAF air development. It was deliberate - and a part of grand strategy - and there was no compromise - all JNAF long range bomber units HAD to be so trained.

