How do you mail a letter to japan?

Letters written in English arrive to Japanese addresses.

The format in Japanese is all one line...

3-7-1-2西新宿東京日本163-1055

The romanji (english alphabet) is in lines like our mailing address.

3-7-1-2 Nishi Shinjuku (3-7-1-2西新宿)

Tokyo (東京)

163-1055 (163-1055)

Japan (日本)

The initial numbers 3-7-1-2 are like our unit/house numbers and street name, the usual grouping is 3 but 4, like this one is not rare for big cities.

Nishi Shinjuku is like our suburb

Tokyo is the state

163-1055 is the postcode.

Some address have another line for the ward.

Eg

104-8-42 Kitta Ikebukuro

Toshima-ku

Tokyo

163-1044

Japan

some endings are

-dai -cho -machi for suburb or town

-ku for ward (borough)

-shi for city

-to -do -fu -ken for prefecture (like a state)