According to Shattered Sword, the B5Ns in the Japanese attack on Midway June 4 carried 800kg land attack bombs, presumably a general purpose HE weapon. It seems an odd choice to me. There would not seem to any targets on Midway which would require a weapon of this power, nor AFAIK were they aiming for precise targets. At Pearl Harbor B5Ns on land attack carried one 250kg and six 60kg bombs, 610kg total, less total weight but likely better coverage against dispersed targets like aircraft, revetments, gun positions, etc. One thing the Japanese were not trying to do was crater the runways on Eastern Island, since they hoped to be using them themselves in a couple of days. So what were the 800kg bombs for?