In the Asia server, IJN DDs have a bit of a bad reputation. Either the first ones to die, the useless DD not even close to a cap, or worse, the DD that goes around the borders to hunt the CV. Of course, other DDs can be prone to these things, but it is IJN DDs that are the more susceptible to it, due to the general lack of AA, knife fight capabilities, and the temptation of flanking due to the generally superior concealment.
Opinions differ as to whether specific IJN DDs need buffs or not, but besides that, I'd like to bring to light as of this juncture on some tidbits that may help your IJN DD play be more consistent, more notably high tiers, also torping overall. As they are usually classified as torp boats, due to their "argumentatively" superior torps, that's where consistent proper torping comes to play a bit more importantly than it does with other lines.
First off, consistency on torping isn't something along the lines of: "Ah, I get 3-4 torp hits every game.". Torping consistency is more a personal evaluation, and is more geared towards having "good salvos that would most likely hit". Consistency should be along the lines of: "I aim to get 15-20 potential torp hits every game". As torping is a two-way process, firstly dependent on how you target your torpedo salvos, the other being how your target dodges your salvos(or lack of dodging). There is RNG in torp spreads, no question there, but it is to the point of being consistent enough not to fail you a lot.
Now, I mention how torping being on those 2 broad factors(player targeting, target dodging). A good torpedo salvo would therefore be a torp salvo that "minimizes" how the target dodges. In a vacuum, open ocean, there are only two spots for torps to approach which one can achieve that. The first is at the most ideal torping spot, which is perpendicular to the target, tilted a bit against the direction they're going. It creates a situation where the enemy is at the worst situation to dodge, and would require more time to properly dodge. [Also known as the CV TB's sweet spot]
The second torping spot is directly bow-on of the target. It is in this case that the only way for them to dodge is for the torp spread RNG to be on their side. As a target, dodging torp salvos that have a torp directly bow on to you, would make it that in order to dodge, you would have to shift the rudder twice[basically wiggle], and speed control is a non-factor.
If you torp in other angles or directions, the target can use "both" rudder shifting and speed control to dodge.
It also goes without saying that the closer you are when you release the salvo, the better.
That's just a torping guideline, now why is it important? For the sake of the subject which is IJN DDs, their torp characteristics have them as having great alpha, flood chance, fast speed, but bad detection range. Hence, minimizing the opponent target's dodging reaction is more important than it is for other DDs. If you want to try it in training room, a GK that has hydro on, can't dodge a Yuugumo spread if it's detected at the worst possible angle which is a small tilt from being perpendicular.
Now, say you have opportunities to hit torps with just that fundamental for now, what makes IJN DD torps potent is their alpha and flood chance. In high tiers, almost every torp hurts be default(except the Germans) . But IJN DD torps have the leisure to cripple a Cruiser at 10-30% HP with 2 torp hits. That's for the alpha.
As for the flood chance, an IJN DD torp hitting anything has a close to 100% or over 100% flood chance, making it actually be able to stack floods. And if you didn't know, with 80s premium DCP cooldown of BBs, successfully stacking a flood on them have around 68% Max HP dealt at T10. Combine it with the alpha most ships already take from just one torp hit, you can almost always guarantee a dead enemy BB with proper flood stacking.
The first argument against doing this would of course be "making sure" the second salvo hits to actually get the flooding to stick. That's where the torping bow-on comes to play. If you torp an opponent bow on, the natural course of action is to NOT turn and present a larger profile to get torped. Making it that they stay in place in the torpedo boats' point of view.
So now, it becomes a choice. Either flank the enemy to get a good angle and go for high alpha dev-strike salvos. Or to prowl the targets head on, and stack floods.
Either choice is potent against BBs, decent against CAs, not really good against DDs.
And it is all of course up to the player, dependent of the situation.
In another standpoint, IJN DD guns aren't really just for decoration. Yuugumo and Shima have a decent enough armament for self defense, which the IJN configuration of 1 bow turret and 2 aft turrets definitely help. They have the most "standard" of arcs, so it's the easiest to get used to. (Very Fast for RU, Fast for the KM DDs, and Slow for the USN). So if consistency with torps is hard, consistency with guns is still achievable. But that's a more niche' choice, not exactly playing with their strength. With things like Radar or Aircraft around, making DD play harder, not only for the IJN.
Another use of torps is flushing out smoke. Especially with RN CLs, a good tidbit to learn is to use your first salvo to torp ahead, THEN torp into the smoke. Conventionally speaking, most people would torp into the smoke then torp ahead. Some would simply throw all of it into the smoke. For the sake of consistency however it's better to torp ahead first, then torp into the smoke. Why? Let's take the enemy PoV first. In the situation that the target sees the torps into the smoke, they will of course accelerate forward, then they'll see the torps ahead. Sure, you can get a hit or two, but it's easier for the target to dodge torps, ONCE he's built up speed. Now reverse that, the enemy sees the torps ahead first, making the course of action, either to stay put or reverse. Then in just a second or two, your second salvo into the smoke will be seen, the enemy is either stopped or in reverse, both of which makes it harder for the target to actually dodge.
All based on the fact that relatively, it's way harder to dodge going in reverse than it is to dodge when you're already going forward. It may not always work, since it's definitely situational, but the little things pile up if you want to do better and better in such torp-centric ships.
There is of course a lot more intricacies in properly torping a target, like actual prediction and estimation. But it's all heavily situational, and I would only like to impart just the little things, small factors that minimize the other player's actions on the result of your own actions. That and just highlighting what the IJN DDs can do better that the other DDs don't do as good. Which the reverse is so heavily known already.
[Most of these situations are of a high tier environment, less nimble ships, BBs that have wide beams, radar is more prevalent, and RN CLs are notorious and DDs have more or less the same concealment ranges]
[Ships of use are the Yuugumo and the Shimakaze]