Danmaku subtitling

Danmaku or Danmu (Japanese: ; Simplified Chinese: , literally translated as “bullet curtain” and figuratively as “barrage”) is a subtitle system in online video platforms that originates from Japan and popularised in Mainland China. Such system allows user to post moving comments onto a playing video that are synchronized to the video timeline. The comments are typically presented as “shooting” across the screen, resembling a barrage. The term Danmaku (だんまく) originates from a shooting arcade game or Shoot 'em up, “Batsugun” created by now-defunct Japanese developer Toaplan. It is a conventional vertically scrolling shooter game, with a "level up" system for the player's weapons that shoot a lot of bullets across the screen, hence the term Danmaku. Batsugun is the first recorded example of what would become Danmaku and subgenres stemming from it. While Batsugun is not credited with actually creating the Danmaku subgenres, it sets a lot of the modern templates in place. Danmaku originated in Japan's video-sharing website Niconico (ニコニコ) in 2006. The videos on the website are mostly generated and uploaded by online users. Niconico provides a comment function which enables viewers to write comments on the screen for the video. The comments will be "shot" onto the screen in a “bullet curtain” likeness, and will be reproduced and displayed in accordance with the time axis thereafter. The comments go beyond real-time, with previous and later comments being shown together. With the rise of Niconico in Mainland China, Chinese video-sharing platforms also began to adopt Danmaku functions, or "Danmu" in Chinese language. Around 2008–2009, Chinese ACG websites AcFun and Bilibili introduced the Danmu system to their video streaming services. Danmu rapidly gained popularity among ACG users in China. Soon, other major Chinese platforms, such as iQiyi, Youku and Tencent Video, followed suit to deploy Danmu. The combination of video and synchronous messaging creates a sense of community for the viewer.