Happi is a traditional Japanese

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 straight-sleeved coat

Coat (clothing)

A coat is a long garment worn by both men and women, for warmth or fashion. Coats typically have long sleeves and are open down the front, closing by means of buttons, zippers, hook-and-loop fasteners, toggles, a belt, or a combination of some of these...

 usually made of indigo

Indigo

Indigo is a color named after the purple dye derived from the plant Indigofera tinctoria and related species. The color is placed on the electromagnetic spectrum between about 420 and 450 nm in wavelength, placing it between blue and violet...

 or brown cotton

Cotton

Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 and imprinted with a distinctive mon (crest). They are usually worn only to festivals. Originally, these represented the crest of a family, as happi were worn by house servants. Later, the coats commonly began to display the crests of shops and organisations. Firefighter

Firefighter

Firefighters are rescuers extensively trained primarily to put out hazardous fires that threaten civilian populations and property, to rescue people from car incidents, collapsed and burning buildings and other such situations...

s in the past also used to wear happi; the symbol on their backs referred to the group with which they were associated. In English, "happi" is most often translated as "happi coat" or "happy coat".