Indeed, despite the fact that the Nazis were both publicly and privately positive about the Japanese alliance, there was actually precious little strategic co-operation or collaboration between the two.
The reasons for this half-heartedness are not entirely clear. It may be that – for all the words of praise – the Nazi leadership were still slightly dubious about their alliance with a non-Aryan people; Goebbels, for instance, made a number of comments to this effect.
However, it seems more likely that the failure to bring the Japanese into the war against the Soviet Union was simply a failure of strategic vision on the part of the Germans. This may be due to Hitler’s tactical myopia – his inability to see the wider global picture – but may also have been motivated by arrogance and by a desire to defeat Stalin’s Soviet Union alone.
Even had a concrete approach been made by the Germans, it is doubtful whether the Japanese would have agreed to the proposal. There were a few within Japanese governing circles who would have been amenable – most notably the foreign minister Matsuoka – but there were also many who were opposed. The powerful vested interests of the imperial navy, for instance, consistently argued in favour of the Nanshinron strategic doctrine – naval deployment to the south, instead of Hokushin – a landbased advance to the north and the west.
Also, it should be remembered that the Japanese already had experience of fighting the Soviets. In August 1939, just before the Nazi invasion of Poland, their army had been routed by Marshal Zhukov at the battles of Khalkhin Gol in eastern Mongolia. It was an experience few in Tokyo wished to repeat.
Answered by Roger Moorhouse, author of Berlin at War (Bodley Head, 2010).