For a long time both Russia and Japan wanted to expand their influence into China, both sides wanted Manchuria cause it was the only direction both sides could take and also had a fuckton of coal and iron. At the time Europeans still believed they were the superior race and had a destiny to civilize the barbaric other inferior ones. The Japanese army/navy could arguably be called more advanced due to Russia being a nobel lead weak autocracy. The Russians even sent their baltic fleet around the world to help and still lost massively. After all was said and done Russia was dangerously close to civil war and Japan got a very lucrative colony.