While perusing the net today I found these statements that were made by Admiral Nagumo proir to the battle. These statements were interpreted from documents that were retrieved by the US during the occupation of Japan. They give a startling insight to the state of the Japanese naval air arm in the time frame between the Coral Sea and Midway battles.
Nagumo's statements:
Although the flight training program was conducted without any major incident, since there had been a considerable turn-over in personnel, practically no one got beyond the point of basic training. Inexperienced fliers barely got to the point where they could make daytime landings on carriers. It was found that even some of the more seasoned fliers had lost some of their skill. No opportunity was available to carry out joint training, which, of course made impossible any coordinated action between contact units, illumination units, and attack units. The likelihood of obtaining any satisfactory results from night attacks, therefore, was practically nil.
Torpedo Attacks:
During the middle part of May, mock torpedo attacks were carried out, with judges from the Yokosuka Air Group acting as referees. The records during these tests were so disappointing that some were moved to comment that it was almost a mystery how men with such poor ability could have obtained such brilliant results as they had in the Coral Sea.
On 18 May, actual tests were made against CruDiv 8 traveling at high speed. In spite of the fact that the speed was 30 knots with only 45-degree turns, the records made by the fliers were again exceedingly poor. With water depth at 40 to 50 meters, about a third of the torpedoes were lost.
Level Bombing:
Bomber leaders were concentrated at Iwakuni and practiced level bombing using the Settsu2 as a target ship. The men attained a fair degree of skill, but they had no opportunity to participate in any formation bombing drills.
Dive Bombing:
Since the Settsu was limited to the waters in the vicinity of Naikai Seibu (Western Inland Sea) valuable time was wasted by the fliers in coming and going. The men could not participate in more than one dive bombing drill a day without seriously interfering with their basic training. Even this minimum practice could not be conducted satisfactorily because the men were kept busy with maintenance work.
Air Combat:
Men engaged in this phase were able to get no further than to actual firing and basic training for lone air combat operations. The more experienced were employed in formation air combat tactics, but even they were limited to about a three-plane formation.
Landing:
Since the carriers were undergoing repair and maintenance operations, the only available ship for take-off and landing drills was the Kaga. She was kept busy from early morning to nightfall but even at that the young fliers barely were able to learn the rudiments of carrier landings. The more seasoned fliers were given about one chance each to make dusk landings.
Night Flying:
Insofar as the weather permitted, men were trained in this phase every day. Due to maintenance needs and because of the limited time, only the very fundamentals were learned by the inexperienced fliers.
Because of the need for replacements and transfers of personnel, the combat efficiency of each ship had been greatly lowered. Moreover, since most of the ships were undergoing maintenance and repair work until only a few days before departure, the men's efficiency suffered greatly.
Training in group formations could not be satisfactorily conducted because of the limitation in time. This was particularly true of the newly formed DesRon 10. Some of the units in it underwent training as anti-air-screening ships, while others were assigned antisub duties. The squadron as a whole never had the opportunity to carry out joint drills.
That was the situation as far as fleet training was concerned. Added to this, we had practically no intelligence concerning the enemy. We never knew to the end where or how many enemy carriers there were. In other words, we participated in this operation with meager training and without knowing the enemy.
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