As much as 桜 (sakura, cherry blossoms) are associated with the start of April, look around at the start of May and you’re likely to see 鯉のぼり (koinobori, carp streamers), which are hung in preparation for こどもの日 (kodomo no hi, Children’s Day) on May 5.
Additionally, in the stores are 五月人形 (gogatsu ningyō), which, as the kanji 五月 (gogatsu, May) and 人形 (ningyō, doll) suggest, are dolls seen around this time of year that mark こどもの日. These little 侍 (samurai, samurai) figurines sport 兜 (kabuto, helmets) and 鎧 (yoroi, body armor), and are meant to celebrate your own little 侍, as こどもの日 traditionally focuses on boys. (The 雛祭 [hinamatsuri, doll’s festival] on March 3 celebrates the girls.)
端午の節句としても知られるこどもの日は、子どもの健やかな成長と幸福を願ってお祝いする日です (Tango no sekku to shite mo shirareru kodomo no hi wa, kodomo no sukoyakana seichō to kōfuku o negatte o-iwai suru hi desu, Also known as the Boy’s Festival, Children’s Day is a day to celebrate and wish for our children to grow up happy and healthy).