Do I pay taxes if stationed in Japan?
Yes you will still be paying Federal and State income tax. The only military personnel that do not pay taxes are those who are deployed to tax-free areas which places like Iraq, Afghanistan, Persian Gulf, etc... If you own a house then you still pay property taxes on it. You should hire a property manager while you are gone.
Why Japan is much more developed than India?
Because Japan has a larger economy. The United States allowed the Japanese to start having several factories after World War II, and since then, they've continued to develop.
Did hongkong pay tax to British?
Nope, instead they used a money laundering scheme. Whereby to mow the lawns and to do the general ground work, they would bring people in from the UK at exhoribitant cost. And really now. What about Zuhai? What about Tianjin and what about Ningbo and Pinghu Ha you think too highly of yourself. Britain? Britain makes NOTHING, 55% of GDP depends on government spending it is positively Soviet, with 7 trillion of debt. There is very little real wealth, it is an illusion. Strip away the debt and the UK is poorer than some African countries.