Tōryanse

"Tōryanse" (通りゃんせ^?) is the name of the traditional Japanese children's tune (warabe uta). It is a common choice for music played by traffic lights in Japan when it is safe to cross.

The words to the song are:

Tenjin-sama no hosomichi ja

This is the narrow pathway of the Tenjin shrine

行きはよいよい　帰りはこわい

Iki wa yoi yoi, kaeri wa kowai

Going in is easy, but returning is scary

There are many theories to the origin of the song, but all agree that it is a portrayal of an exchange between a civilian and a guard manning some sort of a checkpoint — at Kawagoe Castle according to one theory. In the old days when infant mortality was high, people celebrated when a child survived to reach the age of 7 (as well as 3 and 5; see Shichi-Go-San), and ordinary people were only allowed to visit the shrine within the castle compound for special occasions.

This particular warabe uta is sung as part of a traditional game where two children facing each other link their hands to form an arch 'checkpoint', and the remaining children walk through underneath in a line (and back round again in circles). The child who happens to be under the arch when the song finishes is then 'caught'.

The tune being played at Japanese pedestrian crossings is an analogy to this game, i.e., it is safe to cross until the music stops.

Tōryanse can be heard in:

Memories of a Geisha when she's arrive at the Mana the melody plays

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Wikipedia