Somes notes about the Imperial Japanese Navy

[Danelov]

With the inminent "Entry in service" of SHIV and to prepare to entry in theme, some notes about your next "enemy" , the Imperial Japanese Navy.

The IJN was one of the more youngers Navy of the world by 1941, founded by 1871 and following the best model in the world at this time: the Royal Navy.

Japan is a country with very limited availability of raws materials and minerals and the first tentatives of expansions to obtain resources were directed by natural spots near of home:

-The Peninsule of Korea
-China

With this last the younger IJN had started his "Bapteme of Fire" following a few years latter a scalations of tensions with the Imperial Russian forces.
That give place shortly to the Russian-Japanese war by 1904 with a big victoy for the Japanese forces, after battles like Tsushima or Port Arthur .That was also the consagration of the first great japanese Admiral: Heihachiro Togo , the father of the modern IJN.
His insignia ship at Tsushima, the battleship "Mikasa" is still today preserved a Yokosuka.

Other names followed latter to build little a little a wonderfull Navy ,names like Adm Hiraga(creator of the "Yubari" and the excelents "Furutaka","Kako","Aoba and "Kinugasa")and specially the well know Adm Isoruku Yamamoto , CO of IJN fleet from 1939.

THE IJN OF 1941

By 1941 the IJN was the third Navy of the world.
Some remarkable features of the IJN in this time:

-The best Carrier based aviation, deployed in 9 ships(Akagi,Kaga,Soryu,Hiryu,Shokaku,Zuikaku,Ryujo ,Hosho,Zuiho).A 10th carrier was near to entry service, the Shoho, transformation of one submarine depot ship.

The carries were organized in Divisions commanded by very skilled High Rank Officers,specialist in aviation, like Adm Yamaguchi or Ozawa.Less prepared in the theme operations of naval aviation, the Admiral Nagumo, but he had the support,conseils and organisation of two excelents officers, Genda and Fuchida.
As observers of the other countries, the IJN had watched in details the results of the attacks by British planes to Taranto and the results of Matapan.Strategical speaking the IJN carrier force had not egal enemy by 1941.

The training and formation of the pilots was considered also the better worldwide by 1941 utilising also some of the best products of the Japanese aircraft industrie of the time

-Mitsubishi A6M2 "Zero"
-Nakajima B5N2 "Kate"
-Aichi D3A1 "Val"

Also forming parts of the Air Dispositive of IJN , several Kokutais land based of bombers ,fighters and recco planes and floatplanes.
To mention also, the top quality of weapons utilised by the IJN Aviation , torpedos ,cannons
bombs,etc

-Excelent destroyers like the class "Fubuki","Kagero" ,and latter "Yugumo" and "Akizuki" class.
The IJN was specially skilled in the utilisation of destroyer torpedo tactics ,a lot of USN,Australian and British ships had payed the price,specially in the Salomons.
Also to mention, a natural disposition and training to performed well directed night attacks and ambushs.
Excelent optics in the IJN ships , many times enemy forces were sighted before the radar of this last can detect the presence of IJN ships aproaching.Commanders of IJN Destroyers Divisions were also some of the best of the world ,mens like Raiso Tanaka, a "crack" in the famous"Tokyo Express" of the Salomons.

-The battleship line of IJN was considered one of the most formidable in the world.This force included the Kongo class(Kongo,Kirishima, Hiei and Haruna -this ships are more near to be considered as Battlecruisers), Fuso class(Fuso and Yamashiro),Ise Class(Ise and Hyuga),
Nagato class(Nagato and Mutsu) and the formidables Yamato class(Yamato and Musashi, the third example was converted in the supercarrier "Shinano") .
Standard main battery was the 356mm, 406mm in the Nagato´s and 460mm in the Yamato´s

-A good balanced force of cruisers. Heavy cruisers of the IJN were more of a match for many allied ships, "Chokai" class for example, also the force usually was commanded by very skilled Admirals , like Mikawa in Savo Battle.

-Good submarines with incredible performances in range.Some class carried a recco floatplane like the "Glenn" ,and lattter the proyected "Seiran" for the type I-400.Many had carried pocket submarines in the attacks of Pearl Harbour, Madagascar,Diego García,Australian ports,etc.The only bombing operations realised over US territory were done by IJN submarine based floaplanes and cannon fire(also were utilised the explossives ballons).Torpedos of the Long Lance series were the better of the world, with incredible range, speed and explossive effect. One of the most famous torpedo attacks by IJN submarine was the attack by the I-19(Commander Takaichi Kinashi) the 15-09-42 sinken with a salvo the USN Carrier CV-7 Wasp(three torpedos),the destroyer O'Brien DD-415 and damaging with the last torpedo the Battleship North Carolina BB-55.
IJN submarines had also operated in the Indian ocean and in the Atlantic.I-8,I-30,I-29 and I-52 had making operations transport to the french port of Brest.And of course ,this submarines were very wellcome by his colegues of the Kriegsmarine.
Were builded only three submarines of the gigantic I-400 class; this type was tasked to performed a proyected attack to the Panama Canal, utilising for that his complement of 3 "Seirans" bombers each,armed with specials torpedos to destroy the excluses.The IJA(Imperial Japanese Army) had also builded some submarines but utilised only as transports.

THE WEAKEST POINTS OF THE IJN

The IJN strategic line had proyected as main target a definitive battle with his enemie(s) some part near of the Marshall Islands. A battle style Jutland , with dozens of big battleships firing
colossal salvos of shells to destroy the enemy.This target was searched the whole war ,but the USN Admirals like Nimitz were experimented and previsors to avoid and eviting this type of encounter.
Only at Leyte this oportunity come near of be real ,after Halsey had make a serie of strategic mistakes and Kurita was under inmense pressure to arrive a decission and had a clear vission of his very favorable tactical position .

The fleet was builded mainly allround of this objetive. For example subs strategic was the interception of the recco or advanced forces of the enemy or previous damaged warships.Enemy traffic attack was secondary. And that was a great mistake by the IJN , with the USN vulnerable supply line crossing the inmense Pacific.Only one torpedo was allowed to destroy a enemy cargo or tanker.Several USN supply ships damaged by one torpedo,avoid destruction, exactly for this order. This tactic were latter revised but that was too late.

The principes of IJN were fixed allround of a OFFENSIVE force , few attention was gived to the defense ; that is something including in the caracter and temperament of the Japanese
militars generations of this time and his code of conduct.

The results of that , a very weak antisubmarine capacity of IJN. Subchasers were builded very latter in the war after the catastrofic losses in warships and merchant fleet by USN submarines.Destroyers were equipped with a limited number of depth charges , the place was reserved to reinforce AAA or other "really"offensive weapons.Asdic and hydrophones were quite good initially, but near of obsolete after the development of USN submarine tactics by 1943.The programme of construction of Escort Destroyers, like the "Matsu" or "Tachibana" class or the development of IJN AS planes were also too late to change the situation.Convoys were organized latter in the war, specially between Korea-China and Japan ,Philippines-Japan.By early 1942 many ships had sailed independently and the ships losses were minimal by USN submarines.The big chronical problem of the deficient american torpedos had saved in this periode many Japanese cargos and tankers.But the situation start to change drastically by latter 1942 and early 1943.From this periode the IJN start to study the possibility or organisation of convoys , specially tankers and troop transports.But the things were not so easy ,few escorts ships , not destroyers available for escort and the antagonism Army-Navy by the Japanese was too prononced and sometimes a really obstruccion and obstacle.

The AAA of the IJN like many others Navys of this periode was weak, the main AA MG was the 25mm ,a good weapon but only four were carried for example in a "Kagero" class destroyer.The AA battery was improved after the initial operations and by 1945 ,after lossing the umbrella of his carrier fighter protection, the IJN ships were a forest of AAA mounts placed in each space available.Inutil to say , that had augmented the weight of the ships in alarmants proportions.

Optics were excelent in telemeters and other equipment of this nature , but in modern combat is not enough and the radar development was very slow.The first two IJN ships with radar, were utilised in the Midway operation of June 1942.

Many of the planes of the IJN were prived absolutly of armour and protection of vitals parts.
Yes, there were very fast with incredible climb rate and maneuvrablity but also very vulnerable.

The Naval Aviation after the losses in the Battles of Coral Sea,Midway,Santa Cruz.Eastern Salomons,Salomons campaign,etc had few reserves of good trained pilots. The programme of training was accelerated in Japan but the performances and quality of the new pilots was drastically reduced.The apogee of this situation were the catastrofic carrier aviation losses by Ozawa carriers in the Battle of Mariannas in June 1944.

The losses of so many fleet tankers by USN submarines by early 1944 had forced the IJN to utilise the not refined oil of Tarakan to powered his fleet.This oil ,very pure,utilised directly in the boilers ,without refination was also extremely inflamable and volatil.He was the direct responsable of the losses of two of the main carriers of the Ozawa fleet en the Mariannas, Tahio and Shokaku, boths hits by USN submarines.The torpedo hits were not initially fatal for the ships,but shortly, the effect of the gases of the oil exiting of the ruptured fuel tanks had gived way to a serie of incontrolled explossions and furious fires, destroying and sinking both carriers.

The forces or Task Forces were directed at sea , by the Commander of the operation aboard usually of one battleship , like Yamamoto in the Battleship" Yamato" in Midway.That was the traditional form of direct the operations ,but this mode was not always effective,specially for combined great fleets. Radio transmission in a battleship or carrier are far of be ideal at sea to command a so big force, like this one deployed by Yamamoto at Midway.Nimitz had always directed the operations from Pearl Harbour giving his orders to his subordinates like Fletcher or Spruance aboard of the carriers and utilising for that the much more powerfull radio ground instalations.

Few flexibility , a lot of orders in the plans of operations IJN were too rigid ,too complicated, depending of a exact time syncronisation between forces with few possibilities of individual initiatives and taking also few count of possible problems or unwaited situations.Also Nimitz no had fall in this mistake; when he had self considered to not have a clear view of the situation, he had give the initiative to his operatives commanders.

Utilised several times by the IJN the tactic of placing a decoy ,a small force, a small carrier with few destroyers for example(like Eastern Salomons), to attract the USN forces and then engaged with a big strike of a carrier division placed near in ambush or a battleships-cruisers division at night.Operative range circle of IJN Air Groups was always greater as the USN Airgroups(Japanese planes were much less heavy)and more IJN planes can be prepared in the deck of ther carrier in preparation for a strike.(light planes need less lenght to take off from the carrier).

Like the British with the Kriegsmarine , the USN intelligence know the next moves of the IJN.The first desciprage codes were obtained from a sunk IJN submarine,early in the war.
After the death of Yamamoto by the P-38s based at Guadalcanal , the IJN had started to change his security codes.That was a mistake of Washington, partial justified by the sentiments againts the detested Yamamoto still too fresh in the memory of US citizens,autorities and medias after Pearl Harbour.
The order was gived to intercept the plane of Yamamoto and the advantage to know the japanese codes was loss.


I hope that can help you to have a vission of the IJN in your next SHIV.

[Henry_pl]

Probably we're going to see tonnage results never seen before in SH3 :p

I remember my patrols from SH1- FISHING , FISHING, FISHING

Lots of unescorted merchants, sometimes in groups of 4-5, and off course- sampans (just wonderin how is it going to look like- shooting a pile of wood with a deckgun)

[Immacolata]

Great read. My biggest concern is that of the japanese destroyer's quality in submarine warfare. I'd be pretty bored if most of my engagements in SHIV is taking free pot shots at unarmed and unprotected merchants. Were the japanese ASW team as good as the atlantic? And if they were not, isn't this going to make SHIV feel like "easy mode" compared to SH3? Lots of free apples for the picking isn't my idea of a good game. There has to be a challenge.

[Danelov]

Originally Posted by Immacolata

My biggest concern is that of the japanese destroyer's quality in submarine warfare. I'd be pretty bored if most of my engagements in SHIV is taking free pot shots at unarmed and unprotected merchants. Were the japanese ASW team as good as the atlantic? And if they were not, isn't this going to make SHIV feel like "easy mode" compared to SH3? Lots of free apples for the picking isn't my idea of a good game. There has to be a challenge.

Umm, yes really a good theme.No, definitively the IJN ASW team cannot be compared with the allieds in efficience in final results.

The USN loss 52 submarines in WWII , and 45 in action againts the IJN. Not really a brillant "balance" results in more of three years of combat for the IJN antisubmarine forces.

"Easy mode" ,difficult to say, the challenge in the early times for the USN was to obtain some results of his terrible torpedos.Also the fuel theme can be a serious problem in the Pacific, with sometimes so such enorme distances to go to the operative area and back.And same to find some target in this inmense War scenery.

[Immacolata]

Somehow it appears to me like we have set up a game of shooting fish in a barrel. The pacific theatre seems less appealing than the Atlantic if the odds of destruction is a joke. Of course there could be hidden a new game of frustration if you experience your fish bouncing off the enemy ships time after time.

But I hope Ubi will provide some kind of satisfactory replacement for SH3s many breathless moments where you are going deeper and deeper to avoid the punishment of angry destroyers. I assume the IJN did use destroyers for ASW as well?

54 subs lost doesn't sound like a lot compared to the losses of the Kriegsmarine. But how many subs did USN commit?

[edit] Ah, I found an article about the submarine force here. Less typos, as well It is worth a read. 288 or so was commissioned, so 52 means it wasn't a complete turkey shoot. Also the IJN did up the escorting during the war, but as with everything else concerning the war against the US, they didn't have the luck nor the power to do something about it.

RESULTS OF THE AMERICAN PACIFIC SUBMARINE CAMPAIGN OF WORLD WAR II

[Danelov]

To the 45 USN submarines losses against the IJN we can also added ,3 Dutch submarines

K VII the 18-02-42 by IJN planes
K XVI the 25-12-41 by the IJN submarine I-66
O-20 the 20-12-41 by the IJN destroyer Uranami

And the Royal Navy submarines

HMS Porpoise the 19-01-45 by IJN planes
HMS Stratagem the 22-11-44 by IJN destroyer

In all 50 allied submarines destroyed by the IJN in WWII.

[Capt. D]

The following link has some very good comments regarding the pacific, our subs and Japanese ASW.

http://www.valoratsea.com/losses1.htm

The US Sub force had the highest mortality rate of all services. 1 out of 5 submariners were killed. 3,505 men lost their lives.

We had a very good policy, however, in regard to our sub operations - hence "Silent Service"

A Quote from the above site:
"They (Japanese) were prone to accept the most nebulous evidence as positive proof of a sinking, and being sure of a kill, they were off about their business, to let the submarine surface and thank God for the Japanese superiority complex. While 48 submarines were lost in combat operations, and of these, not more than 41 were directly due to to enemy action, the Japanese, at the end of hostilities, furnished us with with information which showed a total of 468 positive sinkings of our submarines. The U.S. Navy, by a wise policy of total censorship of submarine operations, encouraged the enemy in their belief of their anti-submarine successes. When we failed to announce the successful attacks of our submarines, the enemy naturally assumed that the submarines never got home to report them."

Despite what is said here, I do not believe any skipper thought he was invincable and approached every target with the thought "we can't be touched" and on the surface went full speed ahead towards the ship they were after. Yes the Japanese anti submarine tactics were not up to ours yet one had to keep in mind - it only takes one well placed depth charge and it's over.

Happy Hunting

[Steeltrap]

Originally Posted by Immacolata

Great read. My biggest concern is that of the japanese destroyer's quality in submarine warfare. I'd be pretty bored if most of my engagements in SHIV is taking free pot shots at unarmed and unprotected merchants. Were the japanese ASW team as good as the atlantic? And if they were not, isn't this going to make SHIV feel like "easy mode" compared to SH3? Lots of free apples for the picking isn't my idea of a good game. There has to be a challenge.

This is a point I have made in a number of threads. When it comes to the threat level posed by the various ASW forces, the Pacific is a cakewalk compared with the Atlantic. Why?
- the distances are HUGE, so there are plenty of places where there simply is nothing to threaten you (mind you, there's also nothing there, so we're talking a lot of time spent simply getting to/from ops).
- Japanese were ad-hoc about their convoy formation. Important ships - especially troop transports - woiuld be escorted, but there were plenty of single ships or small (5 or fewer) groups with little/no escort.
- many escort vessels were not actually directly part of the IJN (the organisation of this arm of forces is somewhat confusing!).
- Japanese were well behind in significant technologies (especially radar - surprise attacks from the air were very rare - and sonar). This gave American subs substantial advantages compared with the situation in the Atlantic where the escorts had the better technology.

That doesn't mean the sim can't/won't be fun, but don't expect the sort of situation you've faced in the Atlantic. 52 boats is plenty for those on board, but really quite small in comparison with the U-Boats (even in straight % terms). Read some of the excellent books on the subject by those who were there - especially Dick O'Kane on Wahoo and Tang - and compare them with the experiences of U-Boat aces and you'll soon get the idea as to the differences. One item of interest, for example, is that the Pacific often contained thermal layers and subs regularly dived below them and secured from GQ and motored off even while an escort remained on the surface looking for them!! Compare that with the descriptions of Allied ASW efforts by Peter Cremer in U-333....a different world.

[dize]

well well, what should i say. ofc im looking forward to sh4 very much, as every ww2 sim enthusiast. seing the "easyness" of the upcomming subexperience, compared to the atlanitc war, i can only again express my disappointment about the fact that they would not do a sh3 finishing expansion, which would iron out alle the shortcommings of the current sh3. yes i know about gw etc, but these are just mods, who cant deal with the negs, hidden in the hardcoded gamefiles.