How would you have used the IJN?

[lwd]

???

[Karl Heidenreich]

[Bgile]

From a recent study of the damage to South Dakota by Robert Lundgren and Nathan Okun; R Lundgren's summary:

"Overall, the South Dakota class battleships were tough ships. Their internal armor arrangement meant that Japanese AP shells faced a complex set of defenses that would typically remove their nose ballistic and AP caps before they struck the armor plates. The side shell of these ships was strong enough to limit the damage of even the largest Japanese HE caliber shells fired at point blank range. At Guadalcanal, the “All-or-Nothing” armor system worked as her designers intended in limiting structural damage and keeping the ship’s fighting capacities intact."

[Thorsten Wahl]

faced a complex set of defenses that would typically remove their nose ballistic and AP caps before they struck the armor plates.

This finding definately doesnt sound like a all or nothing armor system . But this observation shows an possible defective attachment of AP-caps on japanese shells in general.

HE-shells
The impact speed of HE shells is not as important as the size of the burster charge
the impact speed should be in between 500-700 metres per second, the fuzing of the burster charge was at least four times faster
So any nose fuzed ordnance creates a instant detonation, wich transformes the shell into splinters, before the body of the shell reaches the point of impact, so the 38 mm STS shell plating between second and third deck/ the main deck should be able (in theory) to catch most of the resulting splinters.

The speed of resulting splinters is mostly dependent on the amount of the burster charge,
a general correlation you can find on the following picture

[lwd]

faced a complex set of defenses that would typically remove their nose ballistic and AP caps before they struck the armor plates.

This finding definately doesnt sound like a all or nothing armor system . ...

Why not? The saliant feature of an "all or nothing" armor system was to armor the parts that needed to be armored heavily and not to armor the rest at all in the hopes that any major caliber hits would be "through and throughs" ie not initiate the fuse of the AP shells. Nothing suggest that it can't be a complex scheme as inded the Italians clearly were.

[lwd]

faced a complex set of defenses that would typically remove their nose ballistic and AP caps before they struck the armor plates.

.... But this observation shows an possible defective attachment of AP-caps on japanese shells in general.
...

Does it? Why? Indeed I don't see a reference to "Japanese shells" at least in the quote mentioned. In the actual case of the 14" shell that hit her barbet I'm not sure any battleship AP round would not have been decapped (there seems to be some considerable debate as to whether or not that round was an HE or AP round). It hit the upper deck at a vary oblique angle and penetrated it. Indeed many other rounds might have glanced off.

[Kitsetone]

I would first have secretly withdrawn manyexperienced army units from China. Then I would have backed up the Pearl Harbour assault with a search for the US carriers prearatory to a second strike, avoiding the fuel storage tanks. I would have followed this up by an armed landing with the intention of taking the base. From there, using the base's facilities, I would have have moved up the Combined fleet and moved rapidly against the US Pacific coast with everything Japan had, aiming to cause maximum disruption. If I wanted to get really cheeky, I would have offered the Southern States independence from the Union, under our benvolent guidance.

[RF]

Kitsetone, I don't see this working. I'm not clear what moving second grade troops from China would achieve and you also ignore the logistics involved in the operations against the Philipines, Malaya and the Dutch East Indies. The IJN cannot concentrate on the eastern Pacific at the same time.

Neither will any appeal to the southern states succeed, particulary at a time when Federal funding for projects in the South such as the Tennessee Valley Authority has shown they are better off in the Union than out. The Japs would have done better to bring in Mexico as an ally, with German help.