Dear travelers to Japan: it is recommended to take out an overseas travel insurance.
You can find all information regarding VISAs at the home page of the Ministry of Foreign Affairs of Japan:
Ministry of Foreign Affairs of Japan:VISA / Residing in Japan (in English)
SHORT-TERM STAY
Application Procedures for Single Entry Visas (Nationals of Armenia, Azerbaijan, Belarus, Moldova and Ukraine) (in English).
Application Procedures for Multiple Entry Visas (Nationals of Armenia, Azerbaijan, Belarus, Moldova and Ukraine) (for business purposes only, in English).
WORK OR LONG-TERM STAY
Also, you can find all information regarding VISAs at the home page of the Embassy of Japan in Ukraine (in Russian).
Information regarding IMMIGRATION CONTROL of Japanese and Foreign Nationals (in English).