Original Japanese Gaming of Midway, Pt 3 Just Applying the Rules

Statement of Thesis
The case that I will attempt to make in this section is that there is no evidence that what transpired in the wargames before Midway was anything other than a standard application of the rules to the problem being studied. Though I don't have access to the IJN wargaming manual or rules I will present what the RN 1921 rules [9] say, and make the case that these were at least one possible influence on the IJN rules. I will also present an argument justifying Ugaki's actions describes in  Fuchida & Okumiya with support of a quote from Rubel [10]. Finally I will claim that the results of the gaming on the 25th of May ([7] and previous post) are consistent with what might be expected if the US carriers sortied and and there were an exchange of strikes, so there is no evidence no "cheating" at this point.

The Royal Navy Wargame, 1921
I don't have access to the rules/manuals that the IJN would have been using in 1942, does anyone? However a case can be made that they may well have been influenced by the RN's rules from 1921 [9]. The Anglo Japanese naval treaty (1902-23) expired shortly after the production of the RN's 1921 game, and so may have been available to Japan, or at least discussed between the two navies.

In these rules there is no random element, the results of an attack with a particular weapon system is deterministic, a fixed percentage of bombs/shell etc are deemed hits, but according to the instructions even such results might be adjusted if the result would be unrealistic. This is consistent with what is said, in those sections dealing with  Tactical Exercises  (but not confined to). The following quoted paragraphs give a taste of the relevant instructions:

4. Object of the Tactical Exercises
(i) To practice and test the results obtained in tactical investigations in the most practical manner possible as a preliminary to tests at sea.
(ii) To afford opportunity for practicing decentralisation of command and the full initiative of subordinate commanders in accordance with common doctrine and a particular plan of battle.

Items (iii) through (vi) snipped

5. Conduct of a Tactical Exercise- it is considered that no hard and fast method of assessing damages should be drawn up or adhered to, but that the value of an exercise lies chiefly in drawing attention to, and, where possible, in summing up the main points of the various tactical situations presented during an exercise at the time the occur,. With consequent opportunities for short discussion.

It is of little value to allow an exercise to continue or reach a conclusion if this is not done. Otherwise the situations are forgotten, and if obvious mistakes made by one or more officers taking part are allowed to pass, the results obtained may be entirely false.

A mistake that would obviously not occur in actual practice, but made owing to lack of time for preparation and dissemination of the C in C's tactical ideas, or to the unreal conditions of the tactical table, should at once be pointed out and the move put back and re-moved. This, however, does not apply to mistakes which may obviously occur in actual practice due to the practical difficulties which may obviously occur in actual practice due to the practical difficulties in co-operation on account of visibility etc.

Snip... 

Emphasis above the present author's

Clearly in the RN 1921 rules the redoing of events thought to be unreasonable (such as a fleet deploying before any relevant intelligence was available) would be the norm. Also, the adjustment of a unrealistic number of hits would be adjusted, and if a ship was sunk that on second thoughts should not have been this might well reappear.

The main point here, which is independent of whether the Japanese had access to the RN 1921 rules or not, is that the idea that such games were not competitive, and were to indicate the expected outcome of the operations represented was not a novelty at the time.

Rubel Quote
Rubel who may be considered as something of an authority on professional wargames writes [10]:

  The subjective nature of game-produced knowledge is nowhere clearer than in games that generate information that is bureaucratically or politically threatening to players or sponsors. It is all too easy either to ignore or put a favorable spin on game events or results that do not fit comfortably into existing doctrines or accepted theories. A notable historical example of this phenomenon was a war game conducted by the Japanese Combined Fleet staff prior to the Midway operation. Historians have made much of the fact that the umpires resurrected a Japanese carrier that had been sunk by American aircraft operating out of Midway, citing it as evidence of “victory disease.” In fact, however, the Japanese umpires were perfectly justified—a dice roll had given a highly improbable hit to level-flying bombers (that is, as opposed to dive-bombers), which had proven generally ineffective in attacking ships. They were properly attempting to prevent a capabilities game from becoming a dice game. However, at another point during the game it was asked what would happen if an American carrier task force ambushed Vice Admiral Chuichi Nagumo’s carrier force while it was raiding Midway, and that uncomfortable question seems to have been ignored. The existing plan was based on deception and surprise, tenets and war-fighting values dear to the Imperial Japanese Navy. To acknowledge the existence of an American task force northeast of Midway in a position to ambush Nagumo’s carriers would have been to discount the possibility of surprise. The Japanese planners simply did not want to admit that—it would have negated their plans, and there was no time to start again from scratch.At the very least the game should have suggested more extensive searches in that sector, but the plan was not modified even to that extent. It was easier to ignore this particular game outcome. 

Emphasis above the present author's

Results of the Actual Attacks that were "Adjusted" in the IJN games
If we allow reality to intrude we can look at what actually happened when the Nagumo force was attacked by Midway based aircraft in the battle (which is the gamed incident about which the controversy wages).

The airforces on Midway were significantly stronger than those expected by the Japanese, though possibly not greater than what they would expect had the Americans had sufficient warning of their intentions. From the Nagumo force battle report [11] we know that their estimate of the air strength on Midway was 2 squadrons of reconnaissance flying boats (Catalinas), 1 squadron of Army bombers (B17?), and 1 squadron of fighters. Compared to an actual strength of 32 Catalinas, 6 Avenger Torpedo Bombers, 27 fighters (20 Buffalos, and 7 Wildcats), 27 scout/dive bombers (11 Vindicators, 16 Dauntless), 23 army bombers (4 B26s, 19 B17s) (Prange [4] order of battle).

Soryu under B17 Attack at Midway (Photo# USAF ID 4884)

When attacked piecemeal by the Midway airgroup the Nagumo Force suffered no significant damage, CAP and evasive manoeuvres sufficed to keep them undamaged. This compares with nine, or three hits from high level bombers (which were known to be ineffective against ships free to manoeuvre) in the games. So reality does not contradict the umpires judgement that 9 hits were too many, and second thoughts that even 3 hits were too many.

Concluding remark
One of the surprising things about the Japanese gaming before Midway is that numbers of hits were determined by dice at all, but given that they were it is reasonable to correct for "lucky dice" in the context of the type of exercise in which they were engaged.

We may presume that both F&O knew how the games on Yamato were supposed to be organised (indeed one of them was an umpire in these games) since they were staff officers (at that time or later, but before publication of their book) who had been involved in earlier games of this nature. So we have to ask why they reported these games in the way they did? It is again folklore about the pacific war, but it may have some element of truth in it, that Yamamoto's followers sought to protect his reputation. So the reports of the games could have been an attempt to unload more than his own share of responsibility for the failure of the Midway operation onto Ugaki. It also possibly serves to deflect criticism from F&O for their part in the planning/gaming of the campaign.

References
1. Willson A., War gaming, Pelican Books 1970
2. Curry J. (Ed), Thomas Allen's War Games, Professional Wargaming 1945-1985, History of Wargaming Project 2009.
3. Fuchida M., Okumiya M,, Midway, The Battle that Doomed Japan, Naval Institute Press, 1955
4. Prange G.W., Miracle at Midway, McGraw-Hill, 1982
5. Moulé V.A., A Comparison of Operational Leadership in the Battle of Midway, A paper submitted to the Naval War College as part of the requirements of the Department of Joint Military Operations, 1995
6.Willmott H.P., The Sword and the Javelin, Naval Institute Press, 1983.
7. Parshall, J.B., Tully A.P, Shattered Sword, Potomac Books 2005
8. Goldstein D., Dillon K., The Pearl Harbor Papers, Potomac Books, 1999
9. Curry J. (Ed), The Fred Jane Naval War Game (1906) Including the Royal Navy's Wargaming Rules (1921), The History of the Wargame Project, 2008
10. Rubel R.C., The Epistemology of War Gaming, Naval War College Review, Spring 2006
11.Nagumo force staff, CinC First Air Fleet Detailed Battle Report No. 6, in The Japanese Story of the battle of Midway, ONI Review, May 1947, http://www.ibiblio.org/hyperwar/Japan/IJN/rep/Midway/Nagumo/