Kaiboukan No.4 第四号海防艦
Seiyuu Fujita Saki (藤田咲) Availability Event Drop
Artist [?? Hozuka] (??) Implementation 2020/06/26


Kaiboukan No.4

No.437 第四号海防艦

Type D Coastal Defense Ship

Kaiboukan No.4 Card
Icon HP HP 8 (10) Icon Gun Firepower 3 (15)
Icon Armor Armor 4 (15) Icon Torpedo Torpedo 0
Icon Evasion Evasion 39 (79) Icon AA AA 5 (19)
Icon Aircraft Aircraft 0 Icon ASW ASW 30 (67)
Icon Speed Speed Slow Icon LOS LOS 2 (11)
Icon Range Range Short Icon Luck Luck 18 (76)
Resource Consumption
FuelKai Fuel 10 AmmoKai Ammo 10
Build Time Slots
Unbuildable 1
Stock Equipment Space
DepthCharge Type 3 Depth Charge ProjectorType 3 Depth Charge Projector 045 Card 0
- Locked - -
- Locked - -
- Locked - -
Extra Statistics
Modernization Bonus
Icon AA+1
Scrap Value
FuelKai 1 AmmoKai 1 SteelKai 1
Category Equipment that can be improved with Kaiboukan No.4 as helper ship not found


Kaiboukan No.4 Kai

No.437 第四号海防艦改

Type D Coastal Defense Ship

Kaiboukan No.4 Kai Card
Icon HP HP 15 (17) Icon Gun Firepower 4 (28)
Icon Armor Armor 5 (29) Icon Torpedo Torpedo 0
Icon Evasion Evasion 49 (91) Icon AA AA 11 (40)
Icon Aircraft Aircraft 0 Icon ASW ASW 32 (76)
Icon Speed Speed Slow Icon LOS LOS 4 (20)
Icon Range Range Short Icon Luck Luck 20 (80)
Resource Consumption
FuelKai Fuel 10 AmmoKai Ammo 10
Remodel Level Slots
Level 35 2
Stock Equipment Space
GreenGunDP 12cm Single High-angle Gun Mount Model E12cm Single High-angle Gun Mount Model E 382 Card 0
Xx c - Unequipped - 0
- Locked - -
- Locked - -
Extra Statistics
Remodel Cost
AmmoKai 70 SteelKai 50
Modernization Bonus
Icon Gun+1 Icon AA+1
Scrap Value
FuelKai 1 AmmoKai 1 SteelKai 2
Category Equipment that can be improved with Kaiboukan No.4 Kai as helper ship not found
[Edit]Kaiboukan No.4 Equipment Bonuses
Equipment Extra Requirement Icon Gun Icon Torpedo Icon AA Icon ASW Icon LOS Icon Armor Icon Evasion Note
GreenGunDP12cm Single High-angle Gun Mount Model E12cm Single High-angle Gun Mount Model E 382 Card +2 +1 +2
+ LOS Radar +2 +3
+ AA Radar +2 +3
GreenGunDP12.7cm Single High-angle Gun Mount (Late Model)12.7cm Single High-angle Gun Mount (Late Model) 229 Card (★7+) +1 +1
(★7+) + LOS Radar +1 +4
GreenGunDP12.7cm Single High-angle Gun Mount Kai 212.7cm Single High-angle Gun Mount Kai 2 379 Card +1 +2
+ LOS Radar +1 +4
GreenGunDP5inch Single Gun Mount Mk.30 Kai + GFCS Mk.375inch Single Gun Mount Mk.30 Kai + GFCS Mk.37 308 Card +1 +1



Event Japanese English Note
Play Introduction マル戦計画で生まれた丁型海防艦、その二番艦第四号海防艦でっすー。そうね~ぇ、よつ……って呼んでくれていいよぉ? ていとく、よろしくねぇ! I'm the 2nd ship of the Type-D coastal defense ships that were created under the Maru-Sen Plan, Kaiboukan No.4. Yeah, you can call me "Yotsu" instead. Admiral, happy to work with you. The Maru-Sen Plan was a planned expansion to the navy started in April 1943.
Play Library マル戦計画で生まれた、丁型海防艦、その二番艦、第四号海防艦です。ちっちゃいけれど、ものすごく頑張りました!横須賀の防備や、マリアナや、小笠原。敵の潜水艦だって、負けません。最後は一斉は、松にもらった命頑張りました。 I'm the 2nd ship of the Type-D coastal defense ships that were created under the Maru-Sen Plan, Kaiboukan No.4. I may be tiny but I did my very best defending Yokosuka, Mariana and Ogasawara! Enemy submarines stand no chance. I worked hard right to the end with this life Matsu saved.
Play Secretary 1 は〜い、よつ、呼んだ? Yeees, did you call?
Play Secretary 2 よつにお仕事?ヤルヤル! You have a job for me? You got it!
Play Secretary 3 松の姉御、お疲れさまです。肩こってないですか?よつ、肩もみ上手なんですよ。えぇ?提督もこってるの?じゃあ、提督は、今度もんであげますね。 Big sis Matsu, good work. Are you feeling a bit stiff? I'm good at giving back rubs. Eh? Admiral, you're feeling stiff too? Alright, then I'll rub your back next
Play Idle はぁ、松の姉御、よつ、羊羹とお茶持ってきますね。提督もいる?あ、そうか。じゃあ、よつのと、半ぶつです! Ah, big sis Matsu, I'll go get some youkan and tea. The Admiral's here too? Oh well. Then we'll just split it between us!
Play Secretary Married
Play Wedding
Play Looking At Scores 情報ですね。お待ち下さい。 You want information? Please wait.
Play Joining A Fleet 丁型海防艦、よつ、出撃します。 Type-D coastal defense ship, Yotsu, sortieing.
Play Equipment 1 積みますね。 I'll equip this.
Play Equipment 2 うむ、うむ。 I see, I see.
Play Equipment 3 なんとかなった。 I managed somehow.
 ⇧ shared with expedition selection, resource collection, instant repair and development
Play Supply は〜い、ありがとう。 Yees, thank you.
Play Docking Minor ちょ〜こっと修理です。 I'm going for a quick repair.
Play Docking Major ものすご〜く修理しないと。 I need some biiiiig repairs.
Play Construction は〜い、できました。 Yees, it's done.
Play Returning From Sortie なんとか戻ってこれました。 We managed to make it back.
Play Starting A Sortie 横須賀鎮守府警備海防艦、第四号海防艦、元気です! Yokosuka Naval Base Picket Coastal Defense Ship, Kaiboukan No.4, feeling great!
Play Battle Start 大変、敵だ!敵です! Oh no, it's the enemy! Enemy sighted!
Play Attack こちくんな〜! Stay awaaaaay!
 ⇧ shared with day/night special attacks, support expedition team arrival
Play Night Battle
Play MVP
Play Minor Damage 1 わあぁ! Whoaa!
Play Minor Damage 2 いたい、いたい! Ow, that hurts!
Play Major Damage がははぁ、くらった。うひゃぁ〜、港に戻らないと… Argggh, that did it. Aaah, I have to get back to port...
Play Sunk うっそ…よつ…ここで終わり…?うそだ…姉御ぉ〜… No way... is this... the end for me... It can't be... Big siiiis...




  • Prefers to be called "Yottsu".
  • Very upbeat and energetic, loves to shout at almost all times.


  • Laid down on 5th Oct 1943 she was launched 30th Dec and completed by March 7th '44.
  • As an escort ship she spent most of the war escorting convoys.
  • She is confirmed to have sunk the USS Scamp, and may have sunk the USS Swordfish too, though it cannot be verified.
  • Near the end of the war, She was attacked three times by air strikes each one causing more damage, finally being sunk by planes from HMS Formidable.

See Also

Type D Coastal Defense Ships
Kaiboukan No.4Kaiboukan No.4 Banner
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