Japan's biggest banks are racing to adapt to changing business conditions amid the shrinking population and spread of online banking.

Many have laid out plans to downsize their workforce and massive network of branches while investing in "fintech" — technological innovation in the financial sector — to streamline their operations and make banking more convenient for their customers.

Mitsubishi UFJ Financial Group Inc. is the country's largest financial group by assets, and the red-logoed branches of its core banking unit are a common sight in central Tokyo.