Avant-garde metal, also known as avant-metal or experimental metal, is a subgenre of heavy metal music loosely defined by use of experimentation and characterized by the use of innovative, avant-garde elements, large-scale experimentation, and the use of non-standard and unconventional sounds, instruments, song structures, playing styles, and vocal techniques. Avant-garde metal is influenced by progressive rock and extreme metal, particularly death metal, and is similar to and often overlaps with the similarly experimental progressive metal genre. Some local scenes include Los Angeles, the San Francisco Bay Area, Boston, and Seattle in the United States, Oslo in Norway, and Tokyo in Japan.