Japan seizes French Indiochina

With Entente states suffering from extreme overextension, the thing that scared them the most was unrest in colonies. Finally, it happened.

As more and more soldiers were drafted from the colonies - and the attention of the colonial powers shifted more and more towards Europe - the grip that states participating in the Great War had over their overseas territories began becoming weaker and weaker. This process was mostly stopped by expansive application of thaumaturgy, but it wasn't something instant, but rather a slow process.   In Indiochina the French colonial administration failed to fix the problems before unrest erupted. With most battleworthy soldiers of the Republic being redirected into Europe, the administration had little chance of relief coming. This changed after the Japanese Empire intervened and sent its soldiers to quell the unrest.   While officially done between two allies (even if Japan was barely active in the war against the Central Powers ever since its last colonies in Asia were occupied by the Entente), the Japanese forces didn't move back after the unrest was pacified. Instead, they kept ignoring the issue, while remaining quite cordial with local French administration.   Because of that, while the region was governed by French administration, it was de facto occupied by the Empire of Japan. Causing an increasing rift between the Entente as a whole and Japan, while also causing Siam to join the Entente to gain at least some measures of protection against probable further Japanese expansion.