See, I recall that Germany had actually tried to help Nationalist China before WWII, and I'm not sure exactly what happens if Germany continues to try to make that limited support instead of picking Japan.
IMO this is very unlikely, especially with Ribbentrop as Foreign Minister, but probably even without him. To quote (with slight changes) an old soc.history.what-if post of mine:
***
There is an interesting chapter entitled "Falling between two stools:
Nazi Germany's East Asian Policy" in Christian Leitz, *Nazi Foreign
Policy, 1933-1941: The Road to Global War* (2004) where he notes that the
Third Reich's originally friendly relations with China had their roots in
the Weimar Republic. Both Germany and China (even though the latter was
nominally one of the victors) considered themselves treated unfairly by
the peace settlement. As early as 1921 the Chinese Republic re-
established diplomatic relations with Germany, and "Influential groups
among Germany's business community, but also within the Reichswehr and the
Foreign Ministry, both advocated and actively pursued an improvement of
Germany's relationship to China. In the military spehere, this resulted
in the highly controversial dispatch of German military advisers to
Nanking in 1928, while in the economic field, German-Chinese trade
relations expanded even during the Depression with a growing number of
German companies establishing a presence in the country. From seventh
place among Germany's export markets in 1929, China was to rise to third
place seven years later." (p. 127) Japan, OTOH, was seen as a party to
the oppressive Versailles Treaty (and as late as the early 1930s Japan
failed to provide any support for the efforts of the Papen and Schleicher
governments to reduce the military restrictions imposed on Germany by that
treaty). German industrialists also complained about Japanese
competition, Japanese copying of German goods, etc.
For the first few years of the Third Reich, Hilter showed little interest
in Far Eastern affairs, and the Foreign Ministry, headed by Neurath, tried
to maintain a "balanced" policy toward China and Japan. (For a short
period in the mid-1930s the chief military adviser to Chiang Kai-shek was
none other than Gerneral Hans von Seeckt, one of the Reichswehr's leading
officers during the 1920's.) Ribbentrop was the man who made the most
strenuous efforts (even before he became Foreign Minister) to redirect the
focus of German Far Eastern policy away from China and toward Japan, with
whom he sought a real military alliance, not just the largely
propagandistic Anti-Comintern Pact.
So the question is: Without Ribbentrop, would Hitler still have changed
Germany to a pro-Japanese orientation as he did after the outbreak of the
Sino-Japanese War and especially from 1938 onward? (In 1938, the German
ambassador to China was recalled, and German representation was reduced
to the level of chargé d'affaires; Manchukuo was officially recognized;
and most important, German military advisers were recalled--although a
small number resisted Nazi pressure and remained.) I think the answer is
Yes, because once China lost most of her largest cities to Japan it was
apparent that she could not do much for Germany economically. Moreover,
she was obviously too weak--fighting for her own survival--to be of any
military assistance. Japan, OTOH, was in a position to exert pressure on
the Soviet Union (and to some extent on Britain and France through their
colonies in the Far East) in peacetime and perhaps to be a German ally in
case of war. Also, "The growing realisation that Britain would not
conveniently fall into the position of ally 'alloted' it by Hitler reduced
his concerns about antagonising the British when endorsing Japan's
aggression in Asia." (p. 136)
As Leitz notes, even after 1938 German-Chinese relations--even military
relations--did not completely cease. For example, arms shipments were
gradually curtailed after November 1937, but not stopped entirely: "For a
time, and against Ribbentrop's express wishes, Goering remained clearly
too keen to let the lucrative war material trade with China expire. When
Goering finally ordered the cessation of arms exports to China in April
1938, contracts concluded prior to August 1937 were exempted...As late as
15 October 1939 Goering indirectly acknowledged that such exports had not
yet ceased when he told Sven Hedin that 'we are not at all interested in
the China of Chiang Kai-shek. We have furnished it with war materiel but
are now going to stop these supplies.'" (p. 135) Furthermore, Germany did
not break all diplomatic relations with Chiang's government until 2 July
1941. (p. 134) So Germany did not entirely eliminate relatons with China, but there is no
doubt that from 1938 on her basic orientation was toward Japan, and in
view of the disparity in power between Japan and China, it is hard for me
to see Hitler deciding otherwise, even without Ribbentrop. The only POD
would be a much stronger China and weaker Japan, and that is not something
which German policy in the 1930's would be able to bring about.
https://groups.google.com/d/msg/soc.history.what-if/_Z3OwsIoZLo/7HqJW2WqvSMJ
