What calibre could penetrate Deutschland?

What gun calibre was the Deutschland class protected against?

It depends on range and impact location; even six-inch shells could penetrate weaker areas, and closer ranges increased the threat to heavier protection.

Deutschland's armour cannot be reduced to one calibre that it simply defeats. At longer range the scheme protects more effectively, while closing changes impact conditions and exposes weaker areas. Even six-inch shells could penetrate unarmoured or lightly protected sections and might threaten stronger areas at sufficiently close range. The answer reframes an armour belt as a zone of relative protection rather than an absolute shield.