# S1 No. 1 Style (エスワン ナンバーワンスタイル)
**S1 No. 1 Style** (エスワン ナンバーワンスタイル) is a Japanese adult video (AV) label, described in industry reference material as an in-house brand of the company WILL, launched following MOODYZ.[1](https://tokyoeroticinsider.com/1588/) Its releases carry catalog prefixes such as SSIS, SNIS, and SIVR, and the label is described as one of the most recognized names in the category, with a roster of established performers.[2](https://skdesu.com/en/jav-codes-list/) The official website's copyright notice reads "Copyright © since2004 S1 NO.1 STYLE," which reference material treats as the starting point of its public record rather than as a company founding date.[3](https://www.s1s1s1.com/) • [4](https://jgirl.jp/makers/s1)
| Key fact | Detail |
|---|---|
| Type | In-house AV label of the company WILL, launched following MOODYZ[1](https://tokyoeroticinsider.com/1588/) |
| Public record start | Official site copyright notice dated from 2004; not treated as equivalent to a company founding date[3](https://www.s1s1s1.com/) • [4](https://jgirl.jp/makers/s1) |
| Catalog prefixes | ONED and ONSD from the 2004 launch, then SOE, SNIS, and SSNI; current lines include SSIS, SNIS, and SIVR[1](https://tokyoeroticinsider.com/1588/) • [2](https://skdesu.com/en/jav-codes-list/) |
| SSNI line | Older S1 line running 2016–2021, predecessor of the SSIS series[2](https://skdesu.com/en/jav-codes-list/) |
| Official self-description | 超単体AVメーカー ("super tantai AV maker"), with the catalog organized around actress pages[4](https://jgirl.jp/makers/s1) |
| Signature debut series | 新人NO.1 STYLE, a standing series that collects debut works under one banner[4](https://jgirl.jp/makers/s1) |
| 20th anniversary | A 2024 anniversary project brought together multiple performers in a joint production[4](https://jgirl.jp/makers/s1) |
## Position in the industry
In Japanese AV cataloging, a prefix such as SSIS identifies a label or product line, not necessarily an independent company. S1 No. 1 Style illustrates the in-house pattern: it is described as a label inside the larger company WILL, launched after MOODYZ, another brand in the same corporate structure.[1](https://tokyoeroticinsider.com/1588/) Several unrelated-looking prefixes can therefore sit inside one corporate group, and the corporate relationship can change without the code changing.[1](https://tokyoeroticinsider.com/1588/)
The label's prefix history shows the usual retirement-and-replacement cycle. ONED and ONSD date from the 2004 launch, followed by SOE, SNIS, and SSNI; the SSNI line ran from 2016 to 2021 before the SSIS series superseded it, and SIVR covers virtual-reality releases.[1](https://tokyoeroticinsider.com/1588/) • [2](https://skdesu.com/en/jav-codes-list/)
## The tantai model
S1's official self-description, 超単体AVメーカー, invokes *tantai* (単体), a term for production centered on a single actress. In the scholarly literature on the Japanese AV industry, tantai is contrasted with *kikaku*, production that emphasizes story-based formats; the mid-1990s restructuring of the industry's inspection regime destabilized the hierarchy between the two styles and enabled the hybrid genre kikatan.[5](https://journals.sagepub.com/doi/10.1177/13678779261487209)
S1 applies this actress-centered idea as an editorial structure rather than a popularity ranking. Its official site is organized around performer names: profiles, appearance lists, new-release announcements, and event information gather under each name, and the 新人NO.1 STYLE series gives each debut its own entry in a standing series that connects to a personal page.[4](https://jgirl.jp/makers/s1) A 2023 debut illustrates the pipeline: the talent agency LIGHT promotion announced 望月つぼみ's AV debut under the maker name エスワン ナンバーワンスタイル and the label S1 NO. 1 STYLE, with a release date of May 9, 2023.[6](https://lightpro.jp/news/16.html)
## Anniversary and public presence
For its 20th anniversary in 2024, S1 published a joint project bringing together multiple performers from its history, including 河北彩伽, 田野憂, 榊原萌, 本郷愛, miru, and 七ツ森りり. [Reference material](https://www.edgepedia.org/reference-material) notes that this roster records the 2024 project and is not a current exclusivity list, since performers' affiliations change over time.[4](https://jgirl.jp/makers/s1)
The label maintains official accounts on X and Instagram under the name エスワン〖公式〗, describing itself as a major Japanese AV maker and introducing its actresses; its Instagram account had about 125,000 followers at the time of the retrieved snapshot.[7](https://instagrammernews.com/user/11662664697)
## Name confusion
The similar name SS1 inc. (株式会社エスエスワン) belongs to a Tokyo-based corporate branding company founded on April 17, 1998, with capital of 10,000,000 yen; it is a separate business with no stated connection to the AV label.[8](https://www.ss1.net/)
## References
1. [JAV Codes Explained: How Japanese AV Product Numbers Work, Tokyo Erotic Insider](https://tokyoeroticinsider.com/1588/)
2. [JAV Codes Explained: How Japanese Adult Videos Are Cataloged, Suki Desu](https://skdesu.com/en/jav-codes-list/)
3. [S1 NO.1 STYLE official website (age gate, copyright notice)](https://www.s1s1s1.com/)
4. [S1 NO.1 STYLE | つくり手 | JGirl maker dossier](https://jgirl.jp/makers/s1)
5. [Hoi Yan Yau and Heung Wah Wong, "Regulative production: Genre formation and institutional change in the Japanese adult video industry," International Journal of Cultural Studies (2026)](https://journals.sagepub.com/doi/10.1177/13678779261487209)
6. [Debut announcement for 望月つぼみ, LIGHT promotion news](https://lightpro.jp/news/16.html)
7. [エスワン〖公式〗 Instagram profile, Instagrammer News](https://instagrammernews.com/user/11662664697)
8. [SS1 inc. company website](https://www.ss1.net/)
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*Topic: Encyclopedia › Arts and culture › Screen and stage › Film and television › Screen production organizations › Film studios and distribution › Film studios by country*
*Initially written Sep 17, 2026 · Reviewed: Sep 18, 2026; Oct 25, 2026 · Edited: Sep 18, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license