I've played almost exclusively with the IJN Cruisers and I've recently unlocked the Zao. They might seem painful at first, but keep at it, they're well worth the time investment! Here's some tips:
- First, understand that you just can't get citadelled. IJN Cruisers don't have much armor (they get better with the Mogami though) and bigger citadels, so you just can't take APs to your side. Whenever you see a BB or a CA with big guns (other IJN CAs, American CAs beginning with the Pensacola) shooting APs at you, immediately angle yourself. This means do not expose your broadside unless absolutely necessary. Change your course slightly after each shot and always try to be at the limits of your both guns. Fortunately after the last big patch, the non-BB meta shifted to HE shells so this weakness is not as apparent. Always keep it in mind though.
- When engaged by multiple enemies, always show your bow/stern to the most dangerous enemy. For example, if a BB and 2 CA's are engaging you, move towards/move away directly from the BB while engaging with the CAs. CA's will be shooting HEs at you which'll do much less damage than the AP salvos of the BB. Again, you can't get citadelled.
- The answer to the question "Should I keep my range or close in?" is a very boring "depends". IJN CAs are very flexible so it takes some time to learn when to do what. At the beginning phases of the match, I'd suggest either keeping your range or sneaking into the caps along with your DDs but have an escape plan. The general rule of the thumb for me is; if you're facing multiple enemies, harass from long range. If you're facing 1-2 ships which you're sure you can dispose of, it's not a bad idea to close in. If your enemy is behind an obstacle and is coming out, close in for a surprise torp run.
- Don't forget your torps, but don't think them as your main weapons either. However know that because you have torps, you have the ability to dispose of enemy ships very quickly while US CA's has to rely on HE spam or lucky AP hits. One tactic I really like is doing the "death stare" against single BBs without support. The idea is you rush straight at them without showing your sides. IJN cruisers have a very thin frontal profile so it'll be extremely hard for them to hit you even with a full broadside. Even then they'll mostly be overpenetrating your superstructure doing minimal damage. Spam HE in the meanwhile and get a good fire burning. When you get really close (3-4kms for unavoidable torps) wait for them to waste another salvo, flash your side, drop torps and watch as they disappear. If you miss try again with the other side.
- When you see a DD sitting in smoke, spam torps into the smoke. More often than not you'll get a hilarious free kill. Also spam torps into chokepoints simply because it annoys your enemies (make sure no friendlies are around).
I can go on but I have cook dinner. One last thing though. I can sum up the playstyles I developed for the T5+ IJN CA's like this:
- Aoba: Thinnest frontal profile, not very long along with fast loading guns make this a really good long range harasser.
- Myoko: Again very thin profile, but a lot more guns and 6 torps per side. You can harass at range, but it's also great at closing in, getting AP citadel hits and nuking BBs with torps. This gives you a taste of what to come at higher tiers.
- Mogami: Better armor, but somewhat chubbier. Lowest detection range of them all. 8 torps per side. This a DPS monster. Don't upgrade those guns! You'll absolutely melt/burn everything. I suggest getting the concealment upgrades which let you drop your detection range below 9km. Using that you can force brawls or even do stealth torp runs. You have 9 guns facing forward so you don't even need to expose your broadside in most cases.
- Ibuki: You'll be disappointed and underwhelmed when you first drop with this. It's essentially a Mogami but with forced weapon upgrade and worse concealment and turning radius. BUT you get the repair ability and better armor. The repair ability will repair most of the fire damage you receive from lower tier CAs and keep you in the game longer than them. Though the Ibuki comes to life when you get that gun range upgrade which gives you 19.7km gun range. You can harass other CAs/BBs and most of the time they'll have no way of answering you. This is definitely a ship you want to keep your range with.
- Zao: TBD.