Here's a quote from The Russo-Japanese War and its Shaping of the Twentieth Century by Frank Jacob:
> For Japan, the war against the Czarist Empire was “a colossal enterprise [...] in many ways.”6 With costs of more than 1.7 billion yen, the Russo-Japanese War would put a financial burden on Japanese society for years to come, and since more than one million men were recruited for Japan’s army and navy, a large part of the population directly participated in the war.
More closely this line interests me:
> With costs of more than 1.7 billion yen, the Russo-Japanese War would put a financial burden on Japanese society for 
years to come
This means a loan/loans made it possible for them to wage this war if I put money away to gather a sum for a future expenditure that is a burden on the past, but if I borrow money then it's a burden on the future since I have to pay back after the expenditure. It had to cost a lot ofc, one component of the Japanese victory was equipment, such as the British ships and the German cannons. But the question gives itself:
Who financed Japan?