The Yamato Class Battleships: Japan's over-reliance on superweapons?

You are not far off the money with your statement, but the reason for the apparent Japanese infatuation with these monstrous weapons of warfare requires a little more explanation.

Imperial Japan (and its Navy) entered the post WW1 period in a strong but tenuous position. Over a decade previously they had annihilated the Russians at Tsushima and come of age as a naval power, to the surprise of many. They had built a strong, modern navy in a short period of time (with much foreign support), and had used the handy turmoil of the First World War to sally about the Pacific placing naval bases on various islands and atolls while the worlds premier naval powers slugged at one another for control of the North Sea, and had thus established themselves as major players in the Pacific region. However, they were unsure of their future: The main opponent to any future Japanese expansion into the Pacific would be the USA, who the Japanese knew they could probably never hope to match in terms of equal numbers. The Washington Naval treaty of 1922 limited them to buildng a smaller ratio of battleships than what the other two major naval powers (Britain and the USA) possessed. Had they chose to ignore these pieces of paper and build whatever they damn well pleased they would have been faced with the reality that economically they could not hope to do so. This was not acceptable to Japan, who did not want a future as a second rate power, and nor did they wish to see their naval forces swept away by a numerically superior enemy.

The Japanese response to this was to develop the Kantai Kessen, the doctrine of Decisive Battle. It figured thusly; upon a war with their main potential opponent (The USA), the Japanese navy and associated forces would do its best to wear down an enemy fleet as it moved across the vast Pacific ocean to the point where they felt it reduced enough in size to give them good odds of defeating it in pitched battle, whereupon their battle fleet wold sail out and crush the enemy as decisively as they had done to the Russians at Tsushima. The "wearing down" phase of the plan would utilise the light forces of the IJN such as destroyers and cruisers fighting with the odds as skewed as much as possible in the Imperial Navies favour. This meant night fighting and torpedo warfare, which the Japanese excelled in and trained for obsessively. Submarines would assist with the attrition and harrassment, and naval aviation from aircraft carriers and Pacific islands would cooperate to overwhelm US carrier forces and destroy them. The aspect of the plan the IJN felt less comfortable with was the final fleet clash, as they had serious doubts about their ability to match the USA in both numbers and in terms of quality of ships.

The Japanese problem was their failure to establish and stick to a coherent design doctrine for their capital ships. Japanese battleships could be individually powerful but were often designed as "knee-jerk" ships, built as a response to a threat perceived from newer or rumoured foreign ships. Older ships were extenseively rebuilt to keep them relevant but this led to serious design vices and vulnerabilities due to outdated protection or fire control systems being expected to fight modern enemy vessels. Japanese mediocrity in warship armour schemes and damage control design produced ships regarded as more vulnerable to their American counterparts. Even when the Japanese finally hit upon a design they felt usable as a future template (the excellent Nagato Class), the naval treaty of 1922 scuppered their plans for building more battleships.

The Yamato class was the culmination of these factors. Knowing due to their weaker economy they could not hope to produce sufficient numerical superiority, qualitative superiority was sought. The Yamatos were the masterpiece of this theory, designed to be so massivley powerful they would be able to fight and win against larger enemy forces, compensating for the great expense and complexity which meant so few were produced. In fact the fire control system of the Yamato class was designed with the specific goal of giving them the ability to track and enage multiple enemy battleships at once. As was obvious though, the Yamato class was not the invincible superweapon guaranteed to give the IJN the edge in the Pacific War. In fact their existence could be attributed with some part of the blame for Japans failure; their huge cost meant other aspects of the Japanese naval budget had to be badly neglected, most obviously in light ships, convoy escorts and merchant vessels that the Japanese so desperately needed when US submarines and naval aviation massacred Japanese supply lines and paralysed their war machine. Steel needed for replacing the carriers lost at Midway and the Phillipine Sea was instead locked up in hulls that would never go to join their sister Yamatos, in fact some were retroactively rebuilt as carriers to try too late to make good these losses. However the greatest handicap they represented to the Imperial Japanes Navy was a tactical one. Japan sought desperately throughout the war to chase the dream of a single crushing naval engagement to wipe the USN of the Pacific for good. Yamato and Musashi steamed across the Pacific or waited in vain at anchorages like Truk for reports that the US Pacific fleet was concentrated and close enough to be engaged. In fact, Yamato gained itself the name among its own and other sailors as Hotel Yamato for its time spent in naval bases doing nothing at all. Obviously the USN never wished to give Japan the battle they craved and the Yamato and Musashi went on to their dissapointing and ignomius deaths.