March 2017

My visit to Yushukan, the Japanese military museum located within Yasukuni shrine.


This is a Mitsubishi A6M "Zero" fighter. The Zero is a remarkable aircraft, and its early success contributed to the belief that Japan could succeed militarily. Technically, the Zero was ahead of its time. Its design was in response to a government request for a fighter having almost impossible performance figures as regards range, speed, maneuverability and armament. Only a single designer, Jiro Horikoshi of Mitsubishi, thought it might be possible to meet the design specifications. The key issue was to reduce weight, however, the government stipulated a minimum g-load factor. Horikoshi reasoned that structural elements under tension were more likely capable of returning to their original shape than elements under compression, thus elements under tension (i.e. fuselage longerons) could be designed to lower stress requirements (and therefore be made lighter). The Zero achieved speeds not previously seen; this was all the more remarkable since the engine (~850 HP) was 30-50% less powerful than contemporary US aircraft engines (the US was more advanced in design and manufacture of aeronautical engines than Japan). Under the unusually high speeds of the Zero elevator deflection was far too responsive, forcing pilots to alter their control input as the aircraft speed varied (demanding a much lighter touch at high speed). Horikoshi addressed this issue by having connecting hardware between yolk and elevator stretchable, in so doing, high speed deflections were reduced and the control input by the pilot was the same over a wide range of speed. Mass balances and control tabs on moveable surfaces also reduced the aerodynamic load over a wide range of speeds. Due principally to its lightness and techniques of efficient long range flight the Zero had 2-3x the range of other fighters, and was vastly more maneuverable than other fighters (winning in dogfights). Furthermore, the addition of large caliber canon gave the Zero lethal firepower. The tradeoff was armor protection for the pilot (there was none!) and self-sealing fuel tanks (there were none!). Early on in China and against existing fighters the Zero achieved a kill ratio of around 10 enemy planes shot down for each Zero lost. Thus, Japan had a critical technical advantage in air superiority, and it was felt that 1 zero was worth 5-10 enemy fighters (thus, a relatively small air force could expect to be victorious over a much larger one). This was true at the start of WW2, however, it did not take long for the US, with its vast engineering and manufacturing capability, to produce fighters that outclassed (and vastly outnumbered) the Zero. Japan did not have the resources to rapidly develop and deploy a successor, so the Zero soldiered on until the end of the war - fighting a war of attrition it could not hope to win.


This is a type 89 15 cm fortress cannon. It saw use on one of the islands of the Japanese empire. The notable features of this cannon is the extensive shrapnel damage - most of it is located near the breech, indicating a savage battle, one in which the attackers were targeting the soldiers loading and firing the weapon. Also notable is that there were no survivors among the Japanese soldiers manning this gun. As was commonly the case, they fought until the last man was killed. Surrender was not considered even though the outcome was obvious in advance.


This is an Ohka flying bomb. The entire front half of the plane is a bomb. It is essentially a guided missile - with the pilot serving as the "analog computer" controlling its trajectory. An obvious aspect of the design is the relatively small wing; thus, the aircraft has a high wing-loading and therefore high speed in flight. In the rear of the craft are three solid rocket motors that accelerated the speed to ~500 miles an hour, after which the craft glided to its destination. The small size and high speed made it very difficult to hit with anti-aircraft fire, and the human pilot made it highly adaptable in its flight path. The pilot was, of course, a "consumable".


This is a Kaiten - it was developed from a torpedo into a "manually piloted" torpedo. Japan had the most modern torpedoes in the world during WW2. The notable aspect was that their engines were combustion engines that utilized oxygen-enriched gas as oxidizer. Thus compared to other torpedoes (many of which utilized compressed gas) the Japanese torpedoes left only a very small trail of bubbles (making them difficult to visually spot and avoid), and also gave them a remarkable range (up to 24 miles!).

These weapons consistently demonstrate a remarkably callous attitude towards the average Japanese soldier by the military leaders of the time. Further evidence of this is that, as with any military, there were individual examples of heroism among average soldiers, sailors and pilots, but such acts were not recognized or rewarded (e.g. by commendations or medals). Additionally, while the US would send out flying boats to rescue downed fighter pilots, the Japanese would simply consider such pilots as lost in action. Thus, the expectations of the average Japanese soldier were to sacrifice for the country with little consideration for their humanity or value beyond their military utility. Furthermore, it was obvious early in the war that there was no hope of Japan winning, yet instead of surrendering the military and political leadership felt it was appropriate to consume their soldiers in futile action (in principle, until the last man).  In some sense, the Yasukuni shrine seems to be an effort to redress a past national failing, and recognize the humanity of the WW2 soldiers. As evidence of this, the museum is filled with thousands of pictures of soldiers - providing an individual name and face to the countless fallen.