Question: What is the nationality of "Yen" a Singer-songwriter band?

Context articles: Swallowtail Butterfly (Ai no Uta)
Eloy
Stellar West
Killer BiSH
Rockets (Rockets album)
Enerate
Montage (Yen Town Band album)
Elviss
Yen (band)
Singer-songwriter

"Swallowtail Butterfly (Ai no Uta)" (あいのうた , Suwarōteiru Batafurai Ai no Uta , "Love Song") is a song by Chara, released under the name "Yen Town Band".
 It was the lead single from "Montage", a concept album released for the Shunji Iwai film "Swallowtail Butterfly" that also starred Chara.
 This song was used as the theme song for the film.
Eloy is a German progressive rock band, whose musical style includes symphonic and space rock, the latter theme being more prevalent on earlier albums.
 Despite their nationality and time period, the band is not generally considered krautrock because of their sound, which has much more in common with English progressive rock and symphonic rock groups such as Pink Floyd, King Crimson, Yes, and Camel.
Stellar West is an American rock band from Naperville, Illinois formed in 2014.
 The group consists of Parker Belonio (vocals, guitar), Cole Onley (bass guitar), and Jake Deutschman (drums).
 Their debut release, the EP "Songs From the Basement", was released October 22, 2015 and their first album, "Unfiltered", was released November 13, 2016.
 Both the EP and LP were produced by Adam Krier and engineered by Andy Gerber at Million Yen Studios.
 Pre-production was done at Sound Summit with Adam Krier and Charlie Dresser.
Killer BiSH is the third album by Japanese idol group BiSH released through Avex Trax on October 5, 2016.
 The album is the first full album by the group to be released from a major label.
 The album is the first release to feature new member Ayuni D, who joined the group in August 2016 following the departure of Hug Mii.
 Unlike their independent label albums, songs from the album were not released as free downloads prior to release.
 However, the album was released in its entirety in digital format a month prior to the physical release.
 The first 24 hours of the digital release had all of the group's releases including KiLLER BiSH priced at 300 yen.
 The album was preceded by the single "DEADMAN", released on May 4, 2016.
 The music video for the track "Orchestra" was posted on Youtube on September 9.
 RUKA from Visual-kei band Nightmare, a well known fan of BiSH and BiS, provided the music for the track "IDOL is SHiT".
 The track title is an homage to BiS's album IDOL is DEAD while the track is an homage to the song "IDOL" from that album.
Rockets is the debut self-titled studio album by French space rock band Rockets, released in June 1976.
 It is the only full album by the band to feature vocals in French (albeit, with some English lyrics in two tracks).
 In spite of their nationality, all subsequent albums are sung in English, with the exception of one song on the second and one on the sixth album.
Enerate are a Sydney Based Acoustic Synth Pop group.
 They are based in the Inner West region of Sydney, Australia.
 The Band is currently not signed to a commercial label, and have been releasing material under the independent group "Big Big Records".
 The group have enjoyed early success, with their pre-release single "Unstoppable" getting airplay across Australian digital and standard radio.
 Enerate have played alongside the likes of Samuel Mason, Leroy Lee, and Heavy Yen.
Montage (モンタージュ , Montāju ) is the concept album by Yen Town Band, fictional music group from the 1996 motion picture "Swallowtail" directed by Shunji Iwai.
 The album was actually recorded by a Japanese singer-songwriter Chara who played the starring role in the film.
 It was released by the Sony Music Entertainment Japan in September 1996.
Elviss were a West London-based British alternative rock band, who were active during the mid-2000s releasing only one album titled "Dead Cat and Sharksick" in 2004.
 The album was due to be released in 2003 after the release of their third single "Radio (Kill It)", but it was put back until the band had a hit single.
 It ultimately was never released in their homeland but was released in Japan on 21 April 2004 with a retail price of 2,100 Yen.
 The UK release was due to be 11 tracks only, but the Japanese version had 12 with "Orange Glow" as this track.
 The band's name was a reference to the Enhanced Low light level and Visible Surveillance System (ELVISS).
 During their brief career, they opened for Feeder at a Kerrang!
-sponsored gig and also opened for Stone Sour.
 They were also championed by the magazine itself, which included an appearance at the "Kerrang!
 Weekender" in 2002 at Camber Sands, East Sussex.
 The intro of their "Deadcat and Sharksick" track "Tantrum", was used as an indents soundbed on Kerrang!
's music channel in 2003.
Yen is a German rock band.
 The name of the band stems from singer/songwriter Yen-Hwei Anetzberger.
 "Yen-Hwei" means "Abundant grace" in Mandarin.
Singer-songwriters are musicians who write, compose, and perform their own musical material, including lyrics and melodies.