Hopped into the test server (on its second day so it wouldn't be crowded with super OP TDs puking premium shells like it is now) to check out the new Japanese HT's for you, please note that while the tanks are on test server you cant get a full impression of the vehicles, this is my initial opinion of them. I also compared each tank mostly to the ones of same tier that lead to the HT line of their respective countries.
First, lets start with the Japanese Tech Tree:
-Research cost: 130
-Purchase price: 3,400
The only Medium from the new line. Couldn't play with this tank as no one queues for the lower tiers but will compare his stats with the Chi-Ni:
HP: 200 (+10)
Weight/Load limit (t): 13.31/14.7 (-3.36/-2.7)
Engine Power: 120 (-15)
Top Speed (km/h): 25 (-5)
Traverse Speed (deg/s): 38
Hull armor: 17/15/15 (-8/+3/+5)
Turret Armor: 15/15/15 (-15/-5/-5)
Standart Shell Damage: 56-94
Standard Shell Penetration (mm): 22/37
RoF: 26.9 (+9.25)
Turret Traverse Speed (deg/s): 36 (+6)
View Range: 320 (+20)
Signal Range: 425 (+75)
Same gun, behaves like a HT but has less armor than a MT. Even a FT AC has more hull armor than this, its effective armor may be stronger but I doubt there will be any "normal shell" mercy on low tiers, specially with the anti sealclub system implemented, just glad is a Tier II and easy to pass trough on the grind.
-Research cost: 1,240
-Purchase price: 46,500
I was actually able to get into a battle with this one but was very short lived as I got focused by those in the enemy side.
The Type 91 has one of the biggest HP pools available on tier III, its also one of the heaviest (except for the M2 MT) but its armor is nowhere to be seen, still, in tier by tier comparison is actually better than the Type 89 as it manages to stay statistically between the other tier IIIs (not too bad but not top of line either).
-Research cost: 3,850
-Purchase price: 166,000
Did have a proper battle with this one and ohh baby I like it!
Like the Type 91 it has one of the biggest HP pool except for the Douchebagwagon, cough... sorry the Durchbruchswagen 2, its top speed is the most mediocre but it starts showing signs of armor.
What "shivers me timbers" on this tank its the 7.5 cm gun, it deals the biggest damage for its tier, same top damage as the AMX 40 and my beloved M3lee (but has less penetration than both), also if you wanna be extra evil, use HEAT instead of HE on the angling/sidescrapping enemies, they will "love you long time"!
Type 91, Humble with a pint of Kanye.
-Research cost: 14,730
-Purchase price: 445,000
The first of its kind, and by that I mean the TOG with bewbs kind!
It has the biggest HP pool and I don't know what dark magic the Japanese used because somehow this thing is the heaviest and has the best top speed simultaneously. The armor is not bad either, its actually one of the thickest.
But is with the gun that things get tricky. The 7.5 cm may have the best penetration values but is no match for the 10 cm, a O-I Experimental with a 10 cm gun will easily subdue a 7.5 cm even although it has half the RoF.
And what about the 10 and 12 cm? Well, whatever floats your goat really, the 10 cm is a more reliable gun (better Rof, penetration and accuracy) but the 12 cm does significantly more damage and is actually better than the KV1's 122 mm, it really depends on what type of gameplay you prefer. I personally opted for the 10 cm because there are MT and LT buggers who try to sneak on you and a better RoF and accuracy comes in handy to keep them at bay.
-Research cost: 26,950
-Purchase price: 950,000
Checking the statistics, has the most HP, check! Its the heaviest, check! Hey, where has the speed gone?
Looks like someone had too much "Wagashi" since its experimental days and fattened its armor, the O-I has one of the strongest and Ding Dong! What do we have here... it comes with a 15cm Howitzer Type 96 with better stats than the KV2's 152 mm!
O-I, derping up to 900damage for Sh**s and giggles.
-Research cost: 56,320
-Purchase price: 1,490,000
It has the most HP, just like its predecessors but not by much, the Tiger I have nearly the same, and the slowest except for the Black Prince. The armor is okay except for the sides of the hull which is pretty bad and not handy when you are such a massive rhino with LT and MT hyenas lurking to flank you.
What about the gun? Well, we can still use the 15cm Howitzer Type 96 and the top gun, an 10 cm Experimental that is not that special.
Boring tank, NEXT!
-Research cost: 110,200
-Purchase price: 2,680,000
Highest HP, and as usual the slowest. The armor on the O-Ho is actually significantly better and even although the hull sides are still weak, is not one of the worst.
On the guns, it also has the 15cm Howitzer Type 96 and its top gun an 10 cm Experimental Gun Kai not that special just like O-NI's but reliable enough to keep the grind smooth. Oh, and its signal range is quite good! Definitely a better upgrade.
-Research cost: 177,700
-Purchase price: 3,700,000
Oh boy, I do not like this one...
Nothing new here, Highest HP and the slowest tier IX HT. The armor is pretty good but the mobility just makes me cringe, it doesn't feel as smooth as the other Japanese HT's and had a hard time to enjoy it! I don't have problem with sluggish tanks but this one just doesn't feel right. On the good side, it comes with the tier X gun which is nice.
-Research cost: 257,560
-Purchase price: 6,100,000
The Type 5 is a E-100 and Maus love child who unlike its Type 4 brother has succeeded in life!
Has way more HP, its lighter which gives it more mobility and the armor is pretty good! It has the same 14 cm/50 3rd Year Type gun but its RoF is better. Much more pleasing and fun, actually felt like I wanted to take it to more battles and may actually grind for it! Type 5, the smooth operator!
Although they are very unique and have the biggest HPs in-game and oddly good mobility the Japanese Heavies are very impractical. They get spotted "from a ass of Judas" distance (Portuguese slang for pretty f***ing far away!), their massive size doesn't come in handy and you will have to end up charging around corners giving the sides because there is simply not enough space for sidescraping, they are easily flanked and taken advantage off by faster tanks, if you find yourself alone expect to have the enemy jumping on you like Goblins from Moria once they smell your fresh meat! Oh, and their accuracy matches a drunk guy trying to aim on a urinal.
On the good side, and this may sound weird but... they actually could become one the easiest grinds in the game. Seriously! Let me explain, don't you hate when you are grinding a line and after you are done with an amazing tank you are given a really bad one afterwards that just throws the will away to continue? With the Japanese that wont happen! Simply because they are all... lets put it like this, hard to love!
Gun Rammer, Gun Laying Drive and Vertical Stabilizer.