Someone actually asked me this a while ago, which was largely along the lines of “what/how would a country like Japan use its shipgirls?”
Well, something like this might give you an idea of what the NKT were planning.
Basically, to answer the question, Japan will tend to focus on defending its own home waters. Their military planners are largely pessimistic about the chance of receiving foreign aid once the Abyssal War breaks out, since they really doubt America or the UK would be in a position to come to their rescue.
That, coupled with an inherent belief about Japanese shipgirl superiority, makes it so that Japan’s tendencies to focus on self-sufficiency (okay, technically, all nations do this but Japan emphasizes this) means that they think about fighting the Abyssals in completely different terms.
The two things Kusaka talk about can be summed up basically as follows:
Ambush: Exactly as this sounds. A focus on the (relatively) fast Japanese DD and other light girls to quickly ambush an Abyssal force, or relying on the precision of the Japanese torpedo fairies on DD and subgirls (especially subgirls) to snipe away and destroy the Abyssals in a war of attrition.
Decapitation: This is a call-back to the Kantai Kessen doctrine that the IJN used, but the modern-day NKT believe they have more than the capability to do this. In a suspiciously similar throwback to history, this is basically the idea of luring larger Abyssal forces to (preferably non-Japanese) waters, where an overwhelming strikeforce of the Japanese shipgirls (including the likes of Yamato) can crush the opponent in a single decisive engagement.
The reason, again, is because Japan lack the capabilities of the US. Unlike Avalon, which is a nexus of fairy activity and churns out supply and materiel, the NKT is slow to adapt centralized systems for stockpiling of shipgirl weapons. The Hyuuga Incident was also a critical setback that will likely result in significant delays in at least the foreseeable future.