The Japan Ground Self Defense Force (Nihon Rikujyo Jieitai) is the largest of the three services. The Ground Self-Defense Force (GSDF) operates under the command of the chief of the ground staff, based in the city of Ichikawa, east of Tokyo. Strategy is determined by the nation's elongated insular geography, its mountainous terrain, and the nearness of the Asian mainland. The terrain favors local defense against invasion by ground forces, but protection of the approximately 15,800-kilometer coastline of the four main islands would present unique problems in the event of a large-scale invasion. Potentially hostile aircraft and missile bases are so close that timely warning even by radar facilities might be difficult to obtain. Maneuver space is limited to such an extent that ground defenses would have to be virtually in place at the onset of hostilities. No point of the country is more than 150 kilometers from the sea. Moreover, the straits separating Honshu from the other main islands restrict the rapid movement of troops from one island to another, even though all major islands are now connected by bridges and tunnels. Within each island, mountain barriers and narrow roads restrict troop and supply movements. The key strategic region is densely populated and highly industrialized central Honshu, particularly the area from Tokyo to Kobe. Japan has many places suited for landing operations and is geographically located close to neighboring countries on the continent.
It was extremely difficult, or practically impossible, for Japan to have enough defense capability to repel all troops from the sea in the events of World War III. It incurred enormous and unbearable costs building up a defense capability for the predicted attack. Remarkably, the invasion failed to take a foothold, which lead to the use of Nuclear weapons later. The ground element was neither equipped nor staffed to offer more than a show of conventional defense by itself. However, the determination of that staff escalated the will to stave off the invasion. Antitank artillery, ground-to-sea firepower, and mobility improved and surface-to- ship missiles came to bear to push back the enemy’s campaign. The number of uniformed personnel was insufficient to enable an immediate shift onto emergency footing. Instead, the ratio of officers to enlisted personnel was high, requiring augmentation by reserves or volunteers during the crisis.
Because of population density on the Japanese islands, only limited areas were available for large-scale training, and, even in these areas, noise restrictions were a problem. The GSDF tried to adapt to these conditions by conducting command post exercises and map maneuvers and by using simulators and other training devices. In live firing during training, propellants were reduced to shorten shell ranges. Such restrictions diminished the value of combat training and troop morale. This changed after World War III. After the Japanese Miracle swept over Tokyo, reducing the radiation to a safe background level, the remnants of old Tokyo were split. Half became converted into part of one of the refugee camps while the other found itself the new urban training ground. Noise restrictions were relieved and training continues to the day there.