Buddha's Birthday is held on April 8. Buddhist festival - 灌仏会 - Matsuri, which is held in Japan. It is also referred to as Hana Matsuri, "Flower Festival". This event in the first decade of the month april is annual.
Miyako Odori in Japan on April 1 (The Miyako Odori or 都をどり is one of Japan's best Geisha events. It features a large number of Maiko and several Geiko from the Gion district of Kyoto);
The first day of Takayama Spring Festival on April 14 (Takayama, Gifu, Japan);
Black Day on April 14 (South Korea, Japan, Taiwan. An unofficial holiday celebrated annually by single people - unmarried or unmarried people);
Restoration of Sovereignty Day in Japan on April 28 (主権回復の日 Shuken kaifuku no hi - It marks the end of the American occupation of Japan on 28 April 1952);
Shōwa Day in Japan on April 29 (昭和の日 is celebrated in Japan to commemorate the birth date of Emperor Showa or Hirohito, the emperor of pre and post-World war II)