Circle Four Building Program
Moderators: Joel Billings, wdolson, Don Bowen, mogami
Circle Four Building Program
I am doing some research and am trying to find out the exact ships that were authorized by the Circle Four Japanese Building Program in 1940. I know that there were to be:
1. Two More Yamato's (Shinano plus ???)
2. CV Taiho
3. 6 Planned Escort Carriers (Class/Type???)
4. 6 Cruisers (Type/Class??)
5. 22 DD (Type/Class??)
6. 25 SS (Type/Class??)
Does anyone have this information? I took this much from Kaigun...
1. Two More Yamato's (Shinano plus ???)
2. CV Taiho
3. 6 Planned Escort Carriers (Class/Type???)
4. 6 Cruisers (Type/Class??)
5. 22 DD (Type/Class??)
6. 25 SS (Type/Class??)
Does anyone have this information? I took this much from Kaigun...

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.
- Local Yokel
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RE: Circle Four Building Program
This link on the j-aircraft board may help to take you in the right direction. FWIW, it includes a link to the Japanese language Wikipedia item on Circle 4. A post on the j-aircraft board suggests that 6 Akizuki's formed part of the programme.

RE: Circle Four Building Program
That is a good start. For DDs figure 6 Moon-Class and the rest Fubuki/Standard Japanese DD.
Can anyone find anything on the Cruisers? I would bet on at least a pair of CA but what? Tone-Class again?
Can anyone find anything on the Cruisers? I would bet on at least a pair of CA but what? Tone-Class again?

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- DuckofTindalos
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RE: Circle Four Building Program
Well, the design that later became the Ibuki class were initially intended to be repeat Tones, so there was some thinking along those lines. As for CL's, maybe more Oyodos?
We are all dreams of the Giant Space Butterfly.
- DuckofTindalos
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RE: Circle Four Building Program
BTW, I don't know how realistic you intend your mod to be, but I think you need to be careful when considering exactly how many resources the Japs could devote to this program. It seems unrealistic that this entire sheaf of ships could be built. I especially foresee you having to choose between the fourth Yamato and Taiho.
We are all dreams of the Giant Space Butterfly.
RE: Circle Four Building Program
Hey Terminus.
I am thinking about adding all of the Circle 4 Program into a Mod to allow the Japanese more flexibility in their building during the war. Considering now many of us expand shipyards at the start, this could be a possiblity within the game.
The big change I intend to make though is to cancel the 4th Yamato and replace it with a pair of Taihos or Shokaku-Class CV. Let the option be to complete Shinano as a BB for kicks and grins. Could the Japanese have done this IRL? No. Could the Japanese--potentially--do it in the game...maybe...
I think your comment about the Ibuki-Class cruiser is dead-on. I forgot that she was a conversion. Perhaps two of her class and four more Agano's? Hmmm...
I would prefer to stay with what was planned (exception being the 4th Yamato) to be built...
I am thinking about adding all of the Circle 4 Program into a Mod to allow the Japanese more flexibility in their building during the war. Considering now many of us expand shipyards at the start, this could be a possiblity within the game.
The big change I intend to make though is to cancel the 4th Yamato and replace it with a pair of Taihos or Shokaku-Class CV. Let the option be to complete Shinano as a BB for kicks and grins. Could the Japanese have done this IRL? No. Could the Japanese--potentially--do it in the game...maybe...
I think your comment about the Ibuki-Class cruiser is dead-on. I forgot that she was a conversion. Perhaps two of her class and four more Agano's? Hmmm...
I would prefer to stay with what was planned (exception being the 4th Yamato) to be built...

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.
RE: Circle Four Building Program
One of the DDs atleast was the Shimakaze, as far as I know - Perhaps some of the others were further ships of the same class? (Some sources state 16 in total were planned..)
As for the Ibuki - while the design contemplated in 1940 was similar to the Tone, it was altered in 1942 and would have been more of an improved Mogami class.
I would guess perhaps 2 Ibuki class CA, and atleast 2 Oyodo class CL.
We know this because Oyodo herself was part of this program, as was her sister Niyodo.
The remainder might have been more Agano class CLs.
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Edit;
Ok, from reading http://ja.wikipedia.org/wiki/%E3%83%9E% ... 8%E7%94%BB, Ive noted the following.
The 6 Cruisers were Oyodo and Niyodo, and the 4 Agano class CLs.
Only one Shimakaze class (#125) was included in this plan. The other DDs are 4 Kagero class (#112-115), 13 Yugumo class (#116-124 & #126-129 where #128-129 were never completed), 6 Akizuki class (#104-109). This is 24 ships - If dont count the two unfinished Yugumos, it matches your 22.
As for subs, theres 1 A1 type, 15 B1 type - one of which was not built, 10 KD7 type. This matches the 25 you mention, if you discount the unfinished one.
Ill try look for more info - if anyone finds something that Ive misinterpreted, then please do tell.
So far it looks like most of the smaller ships in the program are already accounted for.
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Extra edit;
Ok, it seems the Ibuki class were actually from the 1941 Supplementary program. Hence why they dont show up in the 4th program.
It seems the link to the page dosent work here, its found halfway down on http://www.j-aircraft.org/smf/index.php?topic=5470.0
As for the Ibuki - while the design contemplated in 1940 was similar to the Tone, it was altered in 1942 and would have been more of an improved Mogami class.
I would guess perhaps 2 Ibuki class CA, and atleast 2 Oyodo class CL.
We know this because Oyodo herself was part of this program, as was her sister Niyodo.
The remainder might have been more Agano class CLs.
----------------------------------------------------------------
Edit;
Ok, from reading http://ja.wikipedia.org/wiki/%E3%83%9E% ... 8%E7%94%BB, Ive noted the following.
The 6 Cruisers were Oyodo and Niyodo, and the 4 Agano class CLs.
Only one Shimakaze class (#125) was included in this plan. The other DDs are 4 Kagero class (#112-115), 13 Yugumo class (#116-124 & #126-129 where #128-129 were never completed), 6 Akizuki class (#104-109). This is 24 ships - If dont count the two unfinished Yugumos, it matches your 22.
As for subs, theres 1 A1 type, 15 B1 type - one of which was not built, 10 KD7 type. This matches the 25 you mention, if you discount the unfinished one.
Ill try look for more info - if anyone finds something that Ive misinterpreted, then please do tell.
So far it looks like most of the smaller ships in the program are already accounted for.
----------------------------------------------------------------
Extra edit;
Ok, it seems the Ibuki class were actually from the 1941 Supplementary program. Hence why they dont show up in the 4th program.
It seems the link to the page dosent work here, its found halfway down on http://www.j-aircraft.org/smf/index.php?topic=5470.0
RE: Circle Four Building Program
Fantastic.
I've found two sources that state the cruisers were two Ibuki (built along the Suzuya lines), two Oyodo, and two Agano.
Your DDs look like a good match to the real count.
I need to go into the WitP database and see how many of those DD are including in the building list.
I've found two sources that state the cruisers were two Ibuki (built along the Suzuya lines), two Oyodo, and two Agano.
Your DDs look like a good match to the real count.
I need to go into the WitP database and see how many of those DD are including in the building list.

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.
RE: Circle Four Building Program
Ive also seen mention of them being in the 4th program, but the Japanese wiki site only makes a reference to 'discontinued two 13,000t cruisers' in the amendments section of the page. However it is very explicit about there being 4 Agano class, going so far as to name each. Its noted that there were originally to be 5, but one was removed from the order.
Their page for the Ibuki class then goes on to state that they were added under the 1941 plan (english wiki agrees with this), and designed as improved Mogami class with minor changes, to be built at Kure (Ibuki) and Nagasaki (sister).
Also worth noting is that both the 5th and 6th programs see a large increase in planned cruisers (including what looks like a class of 4 CLAAs). As these were from 1941/42, it might make more sense for the Ibukis to have come from the same timeframe (1941).
Ill try and dig up more sources, though the japanese wikipedia article is amazingly detailed.
Their page for the Ibuki class then goes on to state that they were added under the 1941 plan (english wiki agrees with this), and designed as improved Mogami class with minor changes, to be built at Kure (Ibuki) and Nagasaki (sister).
Also worth noting is that both the 5th and 6th programs see a large increase in planned cruisers (including what looks like a class of 4 CLAAs). As these were from 1941/42, it might make more sense for the Ibukis to have come from the same timeframe (1941).
Ill try and dig up more sources, though the japanese wikipedia article is amazingly detailed.
RE: Circle Four Building Program
Great work! Could you provide the names for the ships and their respective classes? As I cannot read Japanese, I will have to leave it to you for finding that.
I figure that the Circle Four Program was the last Program Japan had with any chance of laying keels and trying to produce ships. The idea of getting to CHOOSE some ships to be finished and which you cannot would be a lot of fun for a JFB like me!
Thanks for the effort...
I figure that the Circle Four Program was the last Program Japan had with any chance of laying keels and trying to produce ships. The idea of getting to CHOOSE some ships to be finished and which you cannot would be a lot of fun for a JFB like me!
Thanks for the effort...

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.
RE: Circle Four Building Program
The question I have here is---were these 22 DD actually accounted for in the WitP shipbuilding que? I would need names to find out.
ORIGINAL: Elouda
One of the DDs atleast was the Shimakaze, as far as I know - Perhaps some of the others were further ships of the same class? (Some sources state 16 in total were planned..)
As for the Ibuki - while the design contemplated in 1940 was similar to the Tone, it was altered in 1942 and would have been more of an improved Mogami class.
I would guess perhaps 2 Ibuki class CA, and atleast 2 Oyodo class CL.
We know this because Oyodo herself was part of this program, as was her sister Niyodo.
The remainder might have been more Agano class CLs.
----------------------------------------------------------------
Edit;
Ok, from reading http://ja.wikipedia.org/wiki/%E3%83%9E% ... 8%E7%94%BB, Ive noted the following.
The 6 Cruisers were Oyodo and Niyodo, and the 4 Agano class CLs.
Only one Shimakaze class (#125) was included in this plan. The other DDs are 4 Kagero class (#112-115), 13 Yugumo class (#116-124 & #126-129 where #128-129 were never completed), 6 Akizuki class (#104-109). This is 24 ships - If dont count the two unfinished Yugumos, it matches your 22.
As for subs, theres 1 A1 type, 15 B1 type - one of which was not built, 10 KD7 type. This matches the 25 you mention, if you discount the unfinished one.
Ill try look for more info - if anyone finds something that Ive misinterpreted, then please do tell.
So far it looks like most of the smaller ships in the program are already accounted for.
----------------------------------------------------------------
Extra edit;
Ok, it seems the Ibuki class were actually from the 1941 Supplementary program. Hence why they dont show up in the 4th program.
It seems the link to the page dosent work here, its found halfway down on http://www.j-aircraft.org/smf/index.php?topic=5470.0

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.
RE: Circle Four Building Program
Kagero class;
112-Arashi
113-Hagikaze
114-Maikaze
115-Akigumo
Yugumo class;
116-Yugumo
117-Makigumo
118-Kazagumo
119-Naganami
120-Makinami
121-Takanami
122-Onami
123-Kiyonami
124-Tamanami
126-Suzunami
127-Fujinami
(128-?????)
(129-?????)
Shimakaze class;
125-Shimakaze
Akizuki class;
104-Akizuki
105-Teruzuki
106-Suzutsuki
107-Hatsuzuki
108-Niizuki
109-Wakatsuki
112-Arashi
113-Hagikaze
114-Maikaze
115-Akigumo
Yugumo class;
116-Yugumo
117-Makigumo
118-Kazagumo
119-Naganami
120-Makinami
121-Takanami
122-Onami
123-Kiyonami
124-Tamanami
126-Suzunami
127-Fujinami
(128-?????)
(129-?????)
Shimakaze class;
125-Shimakaze
Akizuki class;
104-Akizuki
105-Teruzuki
106-Suzutsuki
107-Hatsuzuki
108-Niizuki
109-Wakatsuki
RE: Circle Four Building Program
OK. Those ships are in the reinforcements already except 128/129. What names did you find for the cruisers?
Does the Japanese Wikipedia mention anything about the 6 CVEs mentioned in Kaigun?
Am headed for bed so I won't write back too soon.
Does the Japanese Wikipedia mention anything about the 6 CVEs mentioned in Kaigun?
Am headed for bed so I won't write back too soon.

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.
RE: Circle Four Building Program
Oyodo class;
Oyodo
Niyodo
Agano class;
Agano
Noshiro
Yahagi
Sakawa
All of these apart from Niyodo are ingame as far as I know.
I would bet the same goes for the submarines, though I havent checked.
Couldnt find anything about CVEs, though there is a mention of 4 seaplane tenders, 3 of which were canceled - the only one completed was Akitsushima. Maybe these were intended to be converted to CVEs much like Chitose?
Also a 5,000t Oiler - another shadow CVE?
Also a mention of a Katori training cruiser - this would be Kashii, completed in 1941. Addition of a second, this is the unfinished Kashiwara. Maybe they finally realise how useless these things were...
The 5th program also makes no mention of CVEs, only the redesign of Taiho. It does include 7 seaplane tenders and 2 seaplane carries. The 5th program also intrestingly includes proposals for 5 more Agano class CLs, the B64/5 Super Cruisers, and the CLAAs I mentioned earlier. It also includes changes to the 4/5th Yamato class, including use of 3.9in AA guns, and a slightly thinner belt - notes on possibility of 18.1in/50 main guns. Also abstracts about Super Yamato class.
The amendement to the 5th program goes really overboard, scrapping almost everything for 5 Taiho class CVs, and if I read it correctly, 13 Unryu class CVs. A little too much a little too late maybe?
----------------------------------------------
Edit;
Ive come to the conclusion that almost all the CVEs are absent from the programs listed there. There are passing mentions of support/assistant aircraft carriers, but nothing more than that.
Perhaps these were authorized on a case by case basis or in some smaller program and not as part of the main naval construction programs? Will do some digging to find out.
Oyodo
Niyodo
Agano class;
Agano
Noshiro
Yahagi
Sakawa
All of these apart from Niyodo are ingame as far as I know.
I would bet the same goes for the submarines, though I havent checked.
Couldnt find anything about CVEs, though there is a mention of 4 seaplane tenders, 3 of which were canceled - the only one completed was Akitsushima. Maybe these were intended to be converted to CVEs much like Chitose?
Also a 5,000t Oiler - another shadow CVE?
Also a mention of a Katori training cruiser - this would be Kashii, completed in 1941. Addition of a second, this is the unfinished Kashiwara. Maybe they finally realise how useless these things were...
The 5th program also makes no mention of CVEs, only the redesign of Taiho. It does include 7 seaplane tenders and 2 seaplane carries. The 5th program also intrestingly includes proposals for 5 more Agano class CLs, the B64/5 Super Cruisers, and the CLAAs I mentioned earlier. It also includes changes to the 4/5th Yamato class, including use of 3.9in AA guns, and a slightly thinner belt - notes on possibility of 18.1in/50 main guns. Also abstracts about Super Yamato class.
The amendement to the 5th program goes really overboard, scrapping almost everything for 5 Taiho class CVs, and if I read it correctly, 13 Unryu class CVs. A little too much a little too late maybe?
----------------------------------------------
Edit;
Ive come to the conclusion that almost all the CVEs are absent from the programs listed there. There are passing mentions of support/assistant aircraft carriers, but nothing more than that.
Perhaps these were authorized on a case by case basis or in some smaller program and not as part of the main naval construction programs? Will do some digging to find out.
- DuckofTindalos
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RE: Circle Four Building Program
By the way, find a different name for the Niyodo. "Niyodo" just means "Oyodo number two".
We are all dreams of the Giant Space Butterfly.
RE: Circle Four Building Program
Well, its written as 仁淀, but if that was ever intended to be its name, who knows. Kinda humourous though.
Oyodo is named after a river in the Miyazaki prefecture in Kyushu. Best bet for an alternate name would be finding something similar. There is always the pre WW1 Yodo, which was scrapped in 1940.
Edit;
Well, it seems Niyodo is a river too. So its a valid name, and a good one too, in my opinion. Comes up with 仁淀川 on the japanese wiki.
Oyodo is named after a river in the Miyazaki prefecture in Kyushu. Best bet for an alternate name would be finding something similar. There is always the pre WW1 Yodo, which was scrapped in 1940.
Edit;
Well, it seems Niyodo is a river too. So its a valid name, and a good one too, in my opinion. Comes up with 仁淀川 on the japanese wiki.
- DuckofTindalos
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- Joined: Fri Apr 22, 2005 11:53 pm
- Location: Denmark
RE: Circle Four Building Program
That's interesting. Every source I've ever seen just said "Niyodo" = "Oyodo #2" so I never bothered looking further. Niyodo is indeed a river.
We are all dreams of the Giant Space Butterfly.
RE: Circle Four Building Program
On the Battleships, this source does give a penant number of 111. Three others, penant numbers 797, 798, & 799 that were cancelled before order.
http://www.hazegray.org/navhist/battleships/ijn_dr.htm
http://www.hazegray.org/navhist/battleships/ijn_dr.htm
Distant Worlds Fan
'When in doubt...attack!'
'When in doubt...attack!'
RE: Circle Four Building Program
Yeah, Hull Numbers 111 & 797 were to be modified the way I detailed above according to the 5th program. 798 & 799 were the two proposed Super Yamato hulls. These were all cancelled in favor of CVs in the amended 5th program.
RE: Circle Four Building Program
Thanks again for all the help! At least now I have some names and specific ship classes to work with. I think it would be fun for the Japanese player to at least have some options when it came to ship construction. This material could help with some of that.
Wonder what some of those emergency CV names were beyond the ones that did get completed? Might be useful to add a few of them that wouldn't come in until WAY late in the war...
Wonder what some of those emergency CV names were beyond the ones that did get completed? Might be useful to add a few of them that wouldn't come in until WAY late in the war...

Member: Treaty, Reluctant Admiral and Between the Storms Mod Team.



