The Japanese Bush Warbler (Japanese: ? uguisu), Cettia diphone, is a passerine bird more often heard than seen. Its distinctive breeding call can be heard throughout much of Japan from the start of spring. Along with the return of the barn swallow the bush warbler's call is viewed by Japanese as a herald of springtime.

Some other Japanese names are haru-dori ("spring bird"), haru-tsuge-dori ("spring-announcing bird") and hanami-dori ("hanami bird" ("spring-flower-viewing bird")). Its place in Japanese poetry (see below) has given the name uta-yomi-dori ("poem-reading bird") and kyo-yomi-dori ("sutra-reading bird"), this latter name because its call is traditionally transcribed in Japanese as "H?-hoke-kyo", which is a phrase from the lotus sutra.

It is one of the favorite motifs of Japanese poetry, featured in many poems including those in Man'y?sh? or Kokin Wakash?. In haiku and renga, uguisu is one of the kigo which signify the early spring. In poetry the bird is associated with the ume blossom, and appears with ume on hanafuda playing cards. There is also a popular Japanese sweet named Uguisu-boru (Uguisu Balls) which consists of brown and white balls meant to resemble ume flower buds. However, the distinctive song is not usually heard until later in spring, well after the ume blossoms have faded.

The beauty of its song led to the English name Japanese Nightingale, though the Japanese Bush Warbler does not sing at night. This name is no longer commonly used.

The bird is drab-coloured and secretive. It is normally only seen in spring before there is foliage in the trees. In winter the call is a low chirping, in haiku the bird with this song is known as sasako, and the song is called sasanaki.

An uguisu-j? (j? = woman) is a female announcer at Japanese baseball games, or a woman employed to advertise products and sales with a microphone outside retail stores. These women are employed because of their beautiful 'warbling' voices. They are also employed to make public announcements for politicians in the lead-up to elections.

In Japanese architecture there is a type of floor known as "uguisubari", which is generally translated into English as "nightingale floor". These floors have squeaking floorboards that resemble the Japanese bush warbler's low chirping, and are meant to be so designed to warn sleepers of the approach of ninja. Examples can be seen at Eikan-d? temple, Nij? Castle and Chion-in temple in Kyoto.

The bird's droppings contain an enzyme that has been used for a long time as a skin whitening agent and to remove fine wrinkles. It is sometimes sold as "uguisu powder". The droppings are also used to remove stains from kimono.

Uguisu-dani is a station on the north part of the Yamanote Line in Tokyo.

Songs This section includes inline links to audio files. If you have trouble playing the files, see Wikipedia Media help.

• Song 1 (info): Pi pi pi... kekyo kekyo Hooo- hoke'kyo Hoohokekyo. Young Japanese Bush Warblers do not initially perform the "hoohokekyo" song skillfully, but gradually learn to sing by imitating others in the vicinity.
• Song 2 (info): Hooo- hokekyo, hooo- hokekyo. The songs of two Japanese Bush Warblers are recorded here on a single file.
• Song 3 (info): Hoohokekyo
• Song 4 (info): Hoohokekyo
• Song 5 (info): Hoohokekyo