Air group, speed, and tempo requirements

The class carried 72 operational aircraft and 12 spares: 18 Mitsubishi A6M Zeros, 27 Aichi D3A Vals, and 27 Nakajima B5N Kates. Its speed slightly exceeded Hiryu's, its protection surpassed Kaga's, and its dual-purpose and light anti-aircraft batteries met the defensive requirement. The air group could handle defense, offense, reconnaissance, and strike missions instead of one narrowly defined task. Eighteen fighters represented the calculated minimum, while the 12 spares could be divided among the three roles to add replacement depth. That reserve mattered because interception-attrition doctrine called for repeated attacks without sending the carrier back to Japan after every loss. The specifications describe the campaign tempo expected from the class as well as its technical performance.