Partials/Opening ASW

The opening anti-submarine attack (OASW) can be performed by any ship with displayed ASW value of 100 or greater (ship's ASW stat + equipment ASW, not counting equipment improvements) and at least one sonar.
- Isuzu Kai Ni is an exception and can always perform the opening anti-submarine attack, even with less than 100 displayed ASW or without any ASW equipment.
- If several ships fulfill the requirements, then they all can perform preemptive attacks, each attacking a random submarine in the enemy fleet. The firing order is determined by the range order, similar to the First Shelling Phase. The order for ships of the same range is random.
- The damage follows the usual ASW formula and is affected by the usual modifiers (formation, engagement, health, ammo), as well as equipment improvements.

The following tables show how much base ASW is needed (in form of required ship level) to enable OASW with a given equipment setup (T4: Type 4 Passive Sonar, T3: Type 3 Active Sonar, DC: Type 3 Depth Charge Projector).

DD
Ship	3 Slots					2 Slots				1 Slot
Ship	T4/T4/T4 36 + 64	T4/T4/T3 34 + 66	T4/T4/DC 32 + 68	T4/T3/DC 30 + 70	T3/T3/DC 28 + 72	T4/T4 24 + 76	T4/T3 22 + 78	T4/DC 20 + 80	T3/DC 18 + 82	T4 12 + 88	T3 10 + 90
Asashio Kai Ni D	85									97	102
Libeccio Kai	60	65	70	75	80	90	95	99	104	119	124
Satsuki Kai Ni	75			78	82	90	94	98	101	113	117
Asashimo Kai	66	70	75	79	84	93	97	102	106	120	124
Ushio Kai Ni	74	79	83	88	93	102	106	111	116	129	134
Верный	77	81	86	90	95	104	108	113	117	131	135
Akizuki Kai Teruzuki Kai Hatsuzuki Kai	81	85	90	95	99	109	114	118	123	137	142
Shigure Kai Ni	83	87	92	97	102	112	116	121	126	141	145
Yuudachi Kai Ni Murakumo Kai Ni Hatsushimo Kai Ni Mutsuki Kai Ni	87	92	97	102	107	116	121	126	131	145	150
Hatsuharu Kai Ni	87	92	97	102	107	117	122	127	132	148	153
Kisaragi Kai Ni	88	92	97	102	107	116	121	125	130	144	149
Fubuki Kai Ni	90	95	99	104	109	118	123	128	132	147	151
Kasumi Kai Ni	90	95	99	104	109	119	124	129	134	149	154
Akatsuki Kai Ni	94	99	105	110	115	126	131	136	141	157	162
Ooshio Kai Ni	99	105	110	115	120	131	136	141	146	162	167
Ayanami Kai Ni Kawakaze Kai Ni	102	107	113	118	123	133	139	144	149	165	170
Shimakaze Kai Yukikaze Kai	115	121	127	134	140	152	158	164	171	189	195

CL/CLT
Ship	3 Slots					2 Slots				1 Slot
Ship	T4/T4/T4 36 + 64	T4/T4/T3 34 + 66	T4/T4/DC 32 + 68	T4/T3/DC 30 + 70	T3/T3/DC 28 + 72	T4/T4 24 + 76	T4/T3 22 + 78	T4/DC 20 + 80	T3/DC 18 + 82	T4 12 + 88	T3 10 + 90
Naka Kai Ni	48	50	55	61	66	77	83	88	94	110	116
Sakawa Kai	63	66	70	74	77	85	88	92	96	107	110
Abukuma Kai Ni	75					82	88	94	99	117	123
Kiso Kai Ni	65	68	72	76	80	88	92	96	99	111	115
Agano Kai Noshiro Kai Yahagi Kai	68	71	75	78	82	89	92	96	99	110	114
Jintsuu Kai Ni	60	65	70	75	80	90	95	99	104	119	124
Kitakami Kai Ni Ooi Kai Ni	71	75	79	82	86	94	98	101	105	117	120
Sendai Kai Ni	72	77	83	88	94	105	110	116	121	138	143