1. Japan is going to invade China, that's for sure. And unlike the 1937 China, the 1913 China is going to be an easy nut to crack.
Whether Japan moves on to invade "China proper" south of the Great Wall from Manchukuo or not, in the eyes of the world, by moving back in time with a Manchukuo puppet state it completely occupies and controls, that was Chinese back in 1913 and included a northern region that was then still a Russian sphere of influence, Japan is *already* seen as invading China and Russia's sphere of influence in it, even without taking any deliberate aggressive steps. It *already* has some explaining to do to Russia, Britain, America, France, Germany, and China, even if they would find, if they probed tactically, they have no capability to push the Japanese out. To the Chinese of 1913, Japanese military superiority would probably look so obvious (seeing tanks and armored cars driving along the frontier, aircraft patrolling the skies) that that the Chinese would not even try to probe. Even 1913 western ships in the Yellow Sea that approach the near waters of Manchuria, Korea and the Japanese islands might see from the looks of Japanese battleships and aircraft carriers, with swarms of aircraft flying overhead, that this IJN is a different kettle of fish, not to be challenged lightly.
]2. Japan is obviously going to bring the knowledge of ww1 to the world. It's possible that ww1 does not happen at all. Some people are also going to be quite unhappy with the fact that Lenin, Hitler and Mussolini exist.
It seems to me that Tokyo's logical move is selectively sharing information from WWI.
With the Americans, French, and British, share nothing at first. Share privately with the German's enough of the WWI story to outline how the Triple Entente powers and America defeated them, confiscated their colonies, dismantled their allies, took away territory, charged reparations, led them to poverty, and led to a recovering Germany signing an anti-COMINTERN Pact and coordination against the Entente's "League of Nations" order by 1936. Share a similar set of details with Italy about the mutilated victory, postwar disillusionment, attempted League sanctions of Italy over Abyssinia, and how resurging Italy aligned with the Anti-COMINTERN pact and pulled out of the League by 1937.
The purpose of these leaks is to suggest Japan has power and knowledge from the future and becomes an ally with them both and suggest that it is wise for them both to align with Japan here and now and work together against common enemies.
For the Russians, possibly leak selected information about WWI breaking out against the Germans and their allies, how it was disaster for Russia leading to revolution, finger all the revolutionary leaders, explain how the revolution led to the rollback of Russian power. Part of the reason is to help get Communists killed. The main part is to slow down Russian anger with Japan about horning in Russia's old sphere in Manchuria, and start discussions about a possible alternate division of spoils in Asia, and to try to plant the seeds that the French, British, and even ultimately Americans all turned out to be inadequate allies for Russia, and Russia should seek other partners, like perhaps Japan and Germany.
For the Chinese, French, British, and Americans, and others - the Japanese owe them no information and should try to prevent any of their uptime citizens in Japanese territory from getting out.
If the Japanese can swing it, they should try to arrange a coalition with the downtime Germans and Italians to deliberately, not accidentally, start war against great power targets one-by-one. And they should invite Russia to join them, actually offer Russia a choice to join them or be an early victim. If Russia is willing to play ball and not be a spoiler, France and its empire can be the first target, then Britain and the Netherlands and DEI. If Russia is playing ball with the early Axis, it can help itself to Persia and northwest China and maybe Iraq or maybe the straits. If Russia squeals or obstructs and sticks with France, it can replace Britain as second victim and get attack from both sides, now with Austria-Hungary, the Ottomans and possibly Romania joining in.
One check on Japan, at least in the short/medium term, would be that can they get certain raw materials, most especially oil sufficient to their needs? Yes they can capture oil sources in the E Asia/SE Asia region but how large is the actual production levels in 1913?
This would probably be less of a problem than you might think.
First of all, the oil-fired ships of the 1930s Japanese fleet will not be competing against enemy 1930s oil-fired ships but worse performing 1910s and 1900s coal-fired ships. Using their stockpiled supply they will probably defeat and disable opponents in critical areas before fuel supplies become a critical problem.
Conquering territory and ports will also capture some fuel supply depots, even of oil. It should also yield capture of coal-fired older adversary ships, and Japan still has a lot of veteran sailors and merchant mariners who know how to operate those. It can end up operating dual fleets the young man's high tech oil-fired fleet and the old reservists coal-fired fleet, supported by land based more modern aviation.
And while it lacks generous oil supplies in northeast Asia, or even Southeast Asia at this time, Manchuria, Korea, and China already have a pretty big coal-mining industry for fueling older ships.
The situation is even better if they are in a working alliance with the Germans and working collaboratively with the portion of the downtime German fleet that is in the far east. That brings up a question - do the Japanese Micronesian mandates that were formerly in 1913 German colonies, go back in time with Japan?
Actually the greatest trumph card of the Japanese is their weakest asset the IJN - even when they do capture DEI oilfields they will have a long haul to develop those to fullfill their national needs.
Though nobody else have Carriers so won't come within firing range of their ships they will still have a years fuel supply capturing DEI or not!This is important, the Japanese may lack fuel to operate carriers and carrier air wings at an intense pace, but their enemies will lack aircraft carriers.....at all, so they won't get close.
