From Setting Sun – Japan in the Pacific War, Penguin Putnam, 1999
Operation Crossbow
Breakout from the bridgeheads
The Japanese Army had managed to amass seven divisions, little more than 100.000 men, to contain the American bridgeheads. Since their initial failure to push the invaders back into the sea, the Japanese High Command had realised that for the decisive battle, they would have to withstand a withering American artillery fire, with battleship and cruisers aplenty sitting in Tokyo bay. Added to that, US naval aviation owned the skies and would harass any Japanese forces unwary enough to be caught moving in daylight.
The Imperial High Command thus discarded all notions of fighting a mobile battle, but instead opted for a rigid defence strategy and ordered their divisions to dig in deep, if possible with fallback positions. In the event field works had barely progressed past the first stages when the American breakout, labelled “Operation Crossbow” began on February 8th.
Second, Fourth and Sixth Armies had been allocated the entire inventory of mobile troops taking part in the invasion, and so each army had two mobile corps, one motorized including three divisions and one breakthrough corps with one armoured and one motorized division. Second Army, having been allotted the open country east of Tokyo in its area of operation had two armoured divisions in its breakthrough corps. The rigid Japanese defence would prove totally unable to contain these mobile formations, although the determined resistance put up by the Japanese troops cost the Americans heavily in blood. The breakout battles saw the heaviest American losses of all the campaign, amounting to close to 15.000 casualties.
Operations of Sixth Army
Elements of Stilwell’s Sixth Army were distributed evenly between the two bridgeheads and both groups drove north, resting one flank on the sea to finally bypass Tokyo itself and join north of the city, isolating the Imperial capital. Only fractions of enemy units remained inside the city itself, which was completely secured by US Marines on February 15th. Needless to say, the Emperor and the Government were long gone. Meanwhile, Stillwell would drive due northeast against minimal resistance through Nagano (taken of February 18th), to reach the Sea of Japan on February 23rd. Stillwell’s advance to the sea had split the main island of Honshu, and the Japanese forces defending it in two: from this point, there was a northern front where three Japanese divisions tried to slow MacArthur down, and a southern one where four Japanese divisions faced Patton.
Operations of Fourth Army
Meanwhile, Patton’s Fourth Army had shattered the western front of the Yokosuka bridgehead under cover of a massive artillery and aerial barrage, rolling up the impromptu enemy fieldworks with ease to drive west. Yokohama with its harbour was taken on the second day while the Japanese fell back in disarray, barely managing through a number of suicidal delaying actions to stay in the field, and only to be driven in front of the advancing American juggernaut. Patton then ran into rugged terrain as he moved both along the coastal highway and the inland Tokyo-Nagoya railroad towards the beaconing prizes of Kyoto and Osaka. Regardless, his tanks were pounding on the gates of the old Imperial capital (restored to that dignity after the fall of Tokyo) by March 1st.
Operations of Second Army
MacArthur on his side encountered more obstacles as he tried to move into the Boso Hanto where the rugged terrain favoured the defenders. Nevertheless, his advantage in numbers and firepower was such that his Second Army was able to push northwest and into more open country on the third day of the attack. He then split his forces to advance north along two axis of advance; the coastal railroad from Tokyo going through Iwaki and Sendai and the inland railroad to Utsunomiya. By the end of the month, all these localities had fallen and Mac was fast approaching Morioka and Akita. Beyond them awaited Amori, the Tsugaru strait and the northern island of Hokkaido.
