DOSSIER · UNCLASSIFIED · OPERATIONS
SECTION 10 // ARMOR / VEHICLE PROFILEREF · O-I
O-I
VI

O-I

JapanJapan·Heavy TankHeavy Tank·HT assault

Development of the superheavy tank was started after the Battles of Khalkhyn Gol in 1939. The vehicle was designed as a maneuverable fire unit that was unprecedented in scale—its hull alone weighed 100 tons. Only one prototype was built, without a turret and made of construction steel. Trials were discontinued due to the unreliable engine; at the end of 1944, the prototype was scrapped. The 15 cm howitzer was to be mounted on the tank after its assembly.

Configuration
Health
1,100
DPM
1,615
View range
370m
Speed
25km/h
Camo
0Terrible
Mark of Excellence requirementsCombined dmg + assist · NA · 2026-08-25
3 marks of excellence
3 marks · 95%
1,846
2 marks of excellence
2 marks · 85%
1,474
1 mark of excellence
1 mark · 65%
978
A-01 · ARMOR SCHEMA

Armor thicknessMeasured

Nominal plate thickness straight from the game client. Click any plate to highlight it on the 3D model and focus the camera on it.

Armor
25mm
150mm

Hull

All 29 plates

Turret

All 11 plates
A-02 · SPECIFICATIONS

Specifications

Builds
Grade
Experimental
CrewShared perks
Field mods
Lv 0/5
Weaponry
DPM
1,615
Damage
700
Penetration
121 mm
… at 500m
109 mm
Reload time
26.00 s
Rate of fire
2.31/min
Aim time
3.70 s
Dispersion
0.580 m
… moving
0.200
… tank traverse
0.200
… turret traverse
0.180
… after firing
4.0
Damage vs. modules
203
Caliber
149.0 mm
Shell velocity
500 m/s
Max range
720 m
Ammo capacity
60
Potential damage
42,000
Shell cost
540 cr
Mobility
Top speed
25 km/h
Reverse speed
10 km/h
Power/weight
8.67 hp/t
Tank traverse
18.0 °/s
Turret traverse
18.0 °/s
Effective top speed
… hard
25.0 km/h
… medium
25.0 km/h
… soft
19.3 km/h
Effective traverse
… hard
18.0 °/s
… medium
15.2 °/s
… soft
11.0 °/s
Gun elevation
20 °
Gun depression
10 °
Gun traverse range
360°
Terrain resistance
… hard
1.10
… medium
1.30
… soft
1.80
Everything Else
Hull armor
150 / 70 / 50
Turret armor
150 / 120 / 60
Health
1,100
Engine health
205
… repaired
103
Track health
210
… repaired
160
… repair time
8.00 s
Ammo rack health
220
… repaired
150
Fuel tank health
200
… repaired
70
Total weight
150,010 kg
Stationary camo
0.20 / 0.00%
Moving camo
0.10 / 0.00%
View range
370 m
Fire chance
20%
Tank cost
950,000 cr
Gun Constraints

360° traverse

Crew
  • Commander
  • Gunner
  • Driver
  • Radio Operator
  • Radio Operator
  • Loader
A-03 · MODULE RESEARCH

Module research

Guns
V
Stock
10 cm Cannon Type 92 (O-I)
VI
14,750
15 cm Howitzer Type 96 (O-I)
Turrets
VI
Stock
O-I
Radios
VI
Stock
Type 96 Mk. 4 Bo
Engines
V
Stock
2x Kawasaki Type 98 Kou (O-I)
VI
27,500
2x Kawasaki Type 98 Otsu (O-I)
Tracks
V
Stock
O-I
VI
6,600
O-I Kai
A-04 · SERVER PERFORMANCE

Server performance

Aggregate stats from NA players over the last 30d

Avg WN8
1268
Good
Avg WNX
1124
aboveAverage
Win rate
48.7%
Below Average
DPG
798
Frags
0.78
Spots
0.63
Survival
24.1%
Dmg taken
1033
Hit rate
66.5%
Spot assist
145
Track assist
24
Defense
0.11
Avg XP
553

Aggregated from 1,691 tracked NA players · 10,488 battles. Coverage grows as more players are tracked.

MoE thresholds (combined dmg + assist)
65%978
85%1,474
95%1,846

Reach these combined damage (dealt + assist) values over a rolling window to earn marks of excellence.

Performance over time

Daily NA 30-day aggregates — how this tank trends as patches and meta shift

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Population spread

How NA players actually perform in this tank (30-day window)

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A-05 · TOP OPERATORS

Top players

Highest performers in the O-I on NA

  1. #1oafusoak101 battles1,748
  2. #2monchito117 battles1,673
  3. #3TheCaptainNapalm141 battles1,669
  4. #4MerlinNP5135 battles1,626
  5. #5IDidOralForFamePoints129 battles1,566
  6. #6Harkonnen25478 battles1,561
  7. #7Osmiy116 battles1,487
  8. #8CharlesDiaper119 battles1,472
  9. #9Mod_Tundra104 battles1,440
  10. #10Shell_Damage141 battles1,439
A-06 · VIDEO INTEL

Video reviews

Curated reviews, replays, and guides from veteran players

No videos yet

Expert reviews and gameplay clips will appear here as they're published.

A-07 · SIMILAR HULLS

Similar tanks

Closest matches by stat profile — pick the ones that fit your playstyle.

A-08 · CHANGELOG

Balance changelog

What changed for this tank between game versions

  1. 2.0Sep 1, 2025
    • Top forward speed29.425
    • Hull rear armor10550
    • Mobility on hard terrain——
    • Mobility on medium terrain——
    • Mobility on soft terrain——
    • Dispersion on hull traverse——
    • Engine2x Kawasaki Type 98 V-12 (550)2x Kawasaki Type 98 Kou (O-I)
    • Power11001200
    • Engine2x Kawasaki Type 98 V-12 (600)2x Kawasaki Type 98 Otsu (O-I)
    • Power12001300
    • Vehicle durability10601100
    • Turret side armor150120
    • Turret rear armor10560
    • GunO-I / 10 cm Cannon Type 92O-I / 10 cm Cannon Type 92 (O-I)
    • Dispersion on turret traverse——
    • Dispersion after firing——
    • AP velocity720800
    • AP* velocity720800
    • GunO-I / 15 cm Howitzer Type 96O-I / 15 cm Howitzer Type 96 (O-I)
    • HE damage radius3.573.53
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