|[[Seiran (631 Air Group)]] (★+4)<br>[[12cm Single High-angle Gun + 25mm Machine Gun]] (★+7)<br>[[14cm Twin Gun Mount Kai 2]] (★+7)<br>[[Late Model Submarine Radar & Passive Radiolocator]] (★+4)
+
|[[Seiran (631 Air Group)]] (★+4)<br>[[12cm Single High-angle Gun Mount + 25mm Machine Guns Additions]] (★+7)<br>[[14cm Twin Gun Mount Kai 2]] (★+7)<br>[[Late Model Submarine Radar & Passive Radiolocator]] (★+4)
−
|[[Seiran (631 Air Group)]] (★+3)<br>[[12cm Single High-angle Gun + 25mm Machine Gun]] (★+4)<br>[[14cm Twin Gun Mount Kai 2]] (★+4)
+
|[[Seiran (631 Air Group)]] (★+3)<br>[[12cm Single High-angle Gun Mount + 25mm Machine Guns Additions]] (★+4)<br>[[14cm Twin Gun Mount Kai 2]] (★+4)
−
|[[Prototype Seiran]] (★+3)<br>[[12cm Single High-angle Gun + 25mm Machine Gun]] (★+2)<br>[[14cm Twin Gun Mount Kai 2]] (★+2)
+
|[[Prototype Seiran]] (★+3)<br>[[12cm Single High-angle Gun Mount + 25mm Machine Guns Additions]] (★+2)<br>[[14cm Twin Gun Mount Kai 2]] (★+2)
|[[Prototype Seiran]] (★+2)<br>[[12cm Single High-angle Gun Mount + 25mm Machine Guns Additions]] (★+1)
+
|-
+
|{{GameUpdates|2024-03-28|text=February}}
+
|[[Type 274 Fire Control Radar]] (★+4)<br>[[Type 281 Radar]] (★+4)<br>[[12.7cm Twin Gun Mount Model C Kai 3]] (★+4)<br>[[Hedgehog (Initial Model)]] (★+3)
+
|[[Type 274 Fire Control Radar]] (★+3)<br>[[Type 281 Radar]] (★+3)<br>[[12.7cm Twin Gun Mount Model C Kai 3]] (★+3)
+
|[[Type 274 Fire Control Radar]]<br>[[Type 281 Radar]] (★+1)<br>[[12.7cm Twin Gun Mount Model C Kai 3]]
+
|[[Type 281 Radar]] (★+1)<br>[[12.7cm Twin Gun Mount Model C Kai 3]]