| "Protostar" | ||||
|---|---|---|---|---|
&sq=Envato&lang=en&file=File:Protostar_Normal_Edition_cover.jpg) Normal edition cover | ||||
| Single by JO1 | ||||
| from the album The Star | ||||
| Language | Japanese | |||
| A-side | "Infinity" | |||
| Released | March 4, 2020 | |||
| Recorded | 2019–2020 | |||
| Genre | J-pop | |||
| Length |
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| Label | Lapone Entertainment | |||
| Producer(s) |
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| JO1 singles chronology | ||||
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| Music video | ||||
| "無限大(INFINITY)" on YouTube | ||||
Protostar (stylized as PROTOSTAR) is an extended play (EP) marketed as the debut single of Japanese boy group JO1, formed through the reality competition show Produce 101 Japan. It also served as the lead single for their first studio album, The Star (2020). Consisting of songs previously performed on the last episode of the show and three new songs, the EP single was released by Lapone Entertainment into three different editions on March 4, 2020. It features the participation of various South Korean songwriters and production teams such as KZ, Kim Seung-soo, Nthonious, KCKT, Ryan S. Jhun, Andrew Choi, and others.
Upon its release, the single earned the top spot on Oricon Singles Chart and received a Platinum certification by the Recording Industry Association of Japan. It made the group became the seventh artist that managed to sell over 300,000 copies in the first week with a debut single according to Oricon. The lead track "Infinity" also peaked atop the Billboard Japan Hot 100.