Combat/Opening Anti-Submarine Warfare

Introduction

During the opening phases of combat, ships which meet certain requirements are able to perform opening ASW attacks. These attacks are valuable because they have the opportunity to sink submarines before they get the chance to perform opening torpedoes.

Overview

1. All ships with an ASW stat are capable of performing OASW.

• Theoretically any ship capable of ASW is able to perform OASW but no equipment exists that allows normal CVL, CAV and BBV to hit the 100 ASW threshold.

2. Upgrades to ASW equipment are not counted towards the thresholds for triggering OASW.

3. OASW attacks are performed in range order.

• Attacks from ships with the same range are random.

4. Damage is calculated the same way as normal ASW.

5. You can modernise a ship's ASW using destroyer escorts. Please see Modernization for more details.

Trigger Requirements

Ship	Requirement
All ASW capable ships	100≤ ASW
Destroyer Escorts	Either: 60≤ ASW with sonar 75≤ ASW with equipment that has 4≤ ASW
Isuzu Kai Ni Tatsuta Kai Ni Jervis Kai Janus Kai Samuel B. Roberts Kai Fletcher Johnston	Default OASW regardless of ASW stat or equipment.
Taiyou Shinyou Gambier Bay Zuihou Kai Ni B	Have both: 65≤ ASW At least 1 plane with 7≤ ASW
Taiyou Kai/Kai Ni Shinyou Kai Kai Ni	65≤ ASW
Hyuuga Kai Ni	Either: 2 Autogyros 1 Helicopter

Minimum OASW Level

The minimum level for OASW can be calculated using:

[math]\displaystyle{ \text{Level}_\text{min} = \bigl\lceil \left( \left(\text{OASW}-\text{ASW}_\text{equip} \right) - \text{OASW}_\text{min} \right) \times \frac{99}{\text{OASW}_\text{max}-\text{OASW}_\text{min}} \bigr\rceil }[/math]

• [math]\displaystyle{ \text{OASW}_\text{min} }[/math] is the minimum ASW of the ship as noted in the tables below.
• [math]\displaystyle{ \text{OASW}_\text{max} }[/math] is the maximum ASW of the ship as noted in the tables below.
• [math]\displaystyle{ \text{ASW}_\text{equip} }[/math] is the total base ASW provided by equipment.
• [math]\displaystyle{ \text{OASW} }[/math] is the relevant OASW threshold.
  • [math]\displaystyle{ 60 }[/math] for DEs with sonars.
  • [math]\displaystyle{ 75 }[/math] for DEs without sonars and ASW equipment that have 4≤ ASW.
  • [math]\displaystyle{ 65 }[/math] for CVLs with 7≤ ASW planes OR Taiyou/Shinyou Kai/Kai Ni
  • [math]\displaystyle{ 100 }[/math] for all other ships.

Minimum OASW Chart

The following apply to the tables below:

• Only easily obtainable equipment combinations are shown.
• The equipment abbreviations are:
  • T4S: Type 4 SONAR
  • T3S: Type 3 SONAR
  • T3DCP: Type 3 Depth Charge Launcher
  • T2DC: Type 2 Depth Charge
  • 931: Type 97 Torpedo Bomber (931 Air Group)
• Ships with default ASW as detailed in the section above aren't listed.
• Numbers in brackets are the total ASW of the equipment setup.
• Only the top remodel is applicable unless otherwise stated.
• If you require minimum OASW levels for remodels or equipment combinations that aren't listed, you can use the formula above and minimum and maximum ASW stats on the ship girl pages.

OASW Tables

Destroyers

Ship	Min ASW	Max ASW
			3 Slots					2 Slots			1 Slot		4 Slots
			T4S/T4S/T4S (36)	T4S/T4S/T3CP (32)	T3S/T3S/T3S (30)	T3S/T3S/T3DCP (28)	T3S/T3DCP/T2DC (25)	T4S/T4S (24)	T3S/T3S T4S/T3DCP (20)	T3S/T3DCP (18)	T4S (12)	T3S (10)	T4S/T4S/T4S/T3DCP (44)	T3S/T3S/T3S/T3DCP (38)	T3S/T3S/T3DCP/T2DC (35)
Asashio Kai Ni D	45	89	85	85	85	85	85	85	85	85	97	102	-	-	-
Urakaze D Kai	45	88	69	69	69	69	70	72	81	86	99	104	-	-	-
Tanikaze D Kai	44	86	70	70	70	70	74	76	85	90	104	109	-	-	-
Maestrale Kai Libeccio Kai	40	80	60	70	75	80	87	90	99	104	119	124	-	-	-
Grecale Kai	38	79	63	73	78	83	90	92	102	107	121	126	-	-	-
Shiratsuyu Kai Ni	30	83	77	77	77	79	85	86	94	98	109	113	-	-	-
Arare Kai Ni	33	81	64	73	77	81	87	89	97	102	114	118	-	-	-
Umikaze Kai Ni	28	82	82	82	82	82	87	88	96	99	110	114	-	-	-
Satsuki Kai Ni	30	81	75	75	78	82	88	90	98	101	113	117	-	-	-
Fumizuki Kai Ni	30	81	77	77	78	82	88	90	98	101	113	117	-	-	-
Asashimo Kai	35	79	66	75	79	84	90	93	102	106	120	124	-	-	-
Kazagumo Kai Ni	29	78	75	79	83	87	93	95	104	108	120	124	-	-	-
Verniy	30	77	72	81	85	89	95	97	106	110	123	127	-	-	-
Yuugumo Kai Ni	30	77	75	81	85	89	95	97	106	110	123	127	-	-	-
Tashkent Kai	40	73	72	84	90	96	105	108	120	126	144	150	50	66	75
Murasame Kai Ni	29	77	73	81	85	89	95	97	106	110	122	126	-	-	-
Shigure Kai Ni	31	76	73	82	86	91	97	99	108	113	126	130	-	-	-
Ushio Kai Ni	32	75	74	83	88	93	99	102	111	116	129	134	-	-	-
Hamakaze B Kai	32	72	80	90	95	99	107	109	119	124	139	144	-	-	-
Makigumo Kai Ni Kishinami Kai Akizuki Kai Teruzuki Kai Hatsuzuki Kai	30	72	81	90	95	99	107	109	118	123	137	142	-	-	-
Hatsushimo Kai Ni	28	72	81	90	95	99	106	108	117	122	135	140	-	-	-
Suzutsuki Kai	28	71	83	93	97	102	109	111	120	125	139	143	-	-	-
Harukaze Kai	22	72	84	92	96	99	105	107	115	119	131	135	-	-	-
Okinami Kai	32	70	84	94	99	105	113	115	126	131	146	152	-	-	-
Kuroshio Kai Ni Isokaze B Kai	31	70	84	94	99	105	112	115	125	130	145	150	-	-	-
Z1 Zwei Z3 Zwei	37	69	84	96	103	109	118	121	134	140	158	164	-	-	-
Arashi Kai	30	70	85	95	99	104	112	114	124	129	144	149	-	-	-
Kamikaze Kai	24	70	87	95	99	104	110	112	121	125	138	143	-	-	-
Hatakaze Kai	21	70	87	95	99	104	110	112	120	124	136	140	-	-	-
Hatsuharu Kai Ni Yamakaze Kai	30	69	87	97	102	107	115	117	127	132	148	153	-	-	-
Mutsuki Kai Ni Murakumo Kai Ni Yuudachi Kai Ni	28	69	87	97	102	107	114	116	126	131	145	150	-	-	-
Matsukaze Kai	20	70	88	96	99	103	109	111	119	123	135	139	-	-	-
Kisaragi Kai Ni	27	69	88	97	102	107	114	116	125	130	144	149	-	-	-
Hayanami Kai	26	69	88	97	102	106	113	116	125	129	143	148	-	-	-
Shiranui Kai Ni Naganami Kai Ni	30	68	89	99	105	110	118	120	131	136	152	157	-	-	-
Kasumi Kai Ni/B Nowaki Kai Hagikaze Kai	28	68	90	99	104	109	117	119	129	134	149	154	-	-	-
Maikaze Kai	27	68	90	99	104	109	116	119	128	133	148	153	-	-	-
Fubuki Kai Ni	26	68	90	99	104	109	116	118	128	132	147	151	-	-	-
Kagerou Kai Ni	30	67	91	102	108	113	121	124	134	140	156	161	-	-	-
Asakaze Kai	18	68	92	99	103	107	113	115	123	127	139	143	-	-	-
Takanami Kai Hayashimo Kai Kiyoshimo Kai	29	67	92	102	107	113	120	123	133	139	154	159	-	-	-
Oyashio Kai	27	67	92	102	107	112	119	122	132	137	151	156	-	-	-
Akatsuki Kai Ni Fujinami Kai	28	66	94	105	110	115	123	126	136	141	157	162	-	-	-
Hamanami Kai	28	65	97	108	113	118	126	129	140	145	161	166	-	-	-
Uzuki Kai	21	65	97	106	111	115	122	124	133	138	151	156	-	-	-
Yamagumo Kai Hatsukaze Kai Akigumo Kai	27	64	99	110	116	121	129	132	142	148	164	169	-	-	-
Ooshio Kai Ni Tokitsukaze Kai	26	64	99	110	115	120	128	131	141	146	162	167	-	-	-
Ayanami Kai Ni Kawakaze Kai Ni	25	63	102	113	118	123	131	133	144	149	165	170	-	-	-
Minazuki Kai	19	61	107	116	121	125	132	135	144	149	163	168	-	-	-
Michishio Kai Ni	26	60	111	123	129	134	143	146	158	164	-	-	-	-	-
Yayoi Kai Nagatsuki Kai Kikuzuki Kai Mikazuki Kai Mochizuki Kai	18	59	112	121	126	131	138	141	150	155	170	174	-	-	-
Asashio Kai Ni Arashio Kai Ni	26	59	114	126	132	138	147	150	162	168	-	-	-	-	-
All other destroyers	24	59	114	125	131	136	145	148	159	165	-	-	-	-	-
Amatsukaze Kai	28	59	115	128	135	141	151	154	167	173	-	-	-	-	-
Yukikaze Kai Shimakaze Kai	27	59	115	127	134	140	149	152	164	171	-	-	-	-	-
Minegumo Kai	24	58	117	129	134	140	149	152	164	169	-	-	-	-	-

Light Cruisers

Ship	Min ASW	Max ASW
			3 Slots					2 Slots			1 Slot		4 Slots
			T4S/T4S/T4S (36)	T4S/T4S/T3CP (32)	T3S/T3S/T3S (30)	T3S/T3S/T3DCP (28)	T3S/T3DCP/T2DC (25)	T4S/T4S (24)	T3S/T3S T4S/T3DCP (20)	T3S/T3DCP (18)	T4S (12)	T3S (10)	T4S/T4S/T4S/T3DCP (44)	T3S/T3S/T3S/T3DCP (38)	T3S/T3S/T3DCP/T2DC (35)
Kinu Kai Ni	49	86	75	75	75	75	75	75	83	89	105	110	-	-	-
Naka Kai Ni	48	85	48	54	59	65	73	75	86	91	108	113	-	-	-
Yura Kai Ni	49	83	77	77	77	77	77	79	91	97	114	120	-	-	-
Abukuma Kai Ni	48	82	75	75	75	75	79	82	94	99	117	123	-	-	-
Tama Kai Ni	43	83	70	70	70	72	80	82	92	97	112	117	-	-	-
Jintsuu Kai Ni	40	80	60	70	75	80	87	90	99	104	119	124	-	-	-
Sakawa Kai	30	84	63	70	74	77	83	85	92	96	107	110	-	-	-
Kiso Kai Ni	32	82	64	72	76	80	86	88	96	99	111	115	-	-	-
Agano Kai Noshiro Kai Yahagi Kai	26	82	68	75	78	82	87	89	96	99	110	114	-	-	-
Kitakami Kai Ni Ooi Kai Ni	27	79	71	79	82	86	92	94	101	105	117	120	-	-	-
Kuma Kai Nagara Kai Natori Kai	24	79	72	80	83	87	92	94	101	105	116	119	-	-	-
Sendai Kai Ni	38	74	72	83	88	94	102	105	116	121	138	143	-	-	-
Tenryuu Kai Ni	24	70	87	95	99	104	110	112	121	125	138	143	-	-	-
Yuubari Kai	24	69	88	97	102	106	113	115	124	128	141	146	71	84	91
Gotland Kai	38	62	108	124	132	141	153	157	174	-	-	-	75	99	112
Giuseppe Garibaldi Kai	25	60	111	122	128	133	142	145	156	162	-	-	88	105	114
Duca degli Abruzzi Kai	25	59	114	126	132	137	146	149	161	166	-	-	91	108	117
Ooyodo Kai	0	39	163	173	-	-	-	-	-	-	-	-	143	158	165

Destroyer Escorts

Ship	Min ASW	Max ASW
			2 Slots			1 Slot
			T4S/T4S (24)	T3S/T3S T4S/T3DCP (20)	T3S/T3DCP (18)	T4S (12)	T3S (10)
Shimushu	32	72	10	20	25	40	45
Kunashiri	31	70	13	23	28	44	49
Ishigaki	32	75	10	19	24	37	42
Hachijou	31	72	13	22	27	42	46
Etorofu Matsuwa Tsushima Fukae	35	72	3	14	19	35	41
Sado	36	73	1	11	17	33	38
Mikura Hiburi	40	78	1	1	6	21	27
Daitou	40	77	1	1	6	22	27

Light Carriers

Ship	Min ASW	Max ASW
			931/931/931 (21)	931/931 (14)	931/ (7)
	Taiyou	35	69	30	47	67
Shinyou	36	60	33	62	91
Zuihou Kai Ni B	32	48	75	118	161
Gambier Bay Kai	30	68	45	55	73