Raid on special bases

[Herode]

I'm playing Japan, July 42, Allies attack Home Island. I have a defensive force : many planes, a few ships, the Allies have a lot of ships but no air superiority.

Since I want air combat but no sea combat, I choose to click on the "Air" button when combat begins. My planes efficiently defend the Home Island and after 2 rounds, the Allies retreat with some losses. Japanese ships endure some hits from dive bombers but not a single one sinks. Nevertheless, on the next turn, 35 ships are required for patrol on Home Island.

I guess I missed something here but I can't figure what. The manual says "Any successful raid on these [special] bases will force the owning player to patrol that base at least with 25% of his fleet strength [...]". Could we have some details about this point ? What is the definition of a successful raid ? Bombs hitting the ground (not the case here) ? A die roll after any attack, maybe depending on the respective forces ? Are air attacks mandatory or can we achieve the same result with a successfull sea attack ? Do any air attack result in forcing patrols, whether it is successuful or not ?

[Strider]

When defending (or attacking) any base, if you don't choose 'Surface' for battles, then the base is considered to be open for ships to close with it. Thus, in your case, you allowed the Allied ships to approach the base close enough to bombard it and succeed, since your defending ships were 'at sea' at air attack only range, and not defending the port.