Were any parts of Russia, China, Mongolia or Japan ever under British rule?

The question is perhaps not as clearly stated as it could be. I took it to read "Were any parts of what today is in Russia, China, Mongolia or Japan ever under British rule?".

If so, Hong Kong comes to mind:

Hong Kong was established as a colony of the British Empire after the Qing Empire ceded Hong Kong Island from Xin'an County at the end of the First Opium War in 1841 then again in 1842. [...] The whole territory was transferred to China in 1997

https://en.wikipedia.org/wiki/Hong_Kong

The Bonin Islands (Japan) were a British possession between 1827 and 1875.
https://en.wikipedia.org/wiki/Bonin_Islands

Weihaiwei (China) was under British rule from 1 July 1898 until 1930 under lease agreement with the Chinese empire
https://en.wikipedia.org/wiki/Weihai

Hong Kong was a port in China that was forcefully leased by the British (at the end of the Boxer Rebellion) for 99 years (the maximum term for a lease). The term was up in 1997, and the Chinese re-took control. They promised the residents that the territory would remain separate and close to what they were used to, but that is slowly changing to one rule for all of China. The British were a great sea faring nation dependant upon ports to carry out trade. Mongolia had no ports, so no interest in them. Russia and Japan traded freely, but China had sealed off their ports to Western traders. Owning Hong Kong opened the country to them.