This iM@S video is supposedly for the 2003 AM Show. The first iM@S ever released the 2005 arcade game. That game was supposedly first “unveiled” in 2004.
So, how do all the dates add up?
I’ll go through the iM@S timeline I found while researching for my Timeline project, as well as some nuggets of connections to other properties. Note that I am not fluent in Japanese so all this might be easier if one could read and understand the nuances of the language of the Japanese sources.
The copyright in the video says 2003 by NAMCO. Most sources agree that the first “The iDOLMASTER” (iM@S) ever released in the franchise was on 2005 July 26 as an arcade game. Wikipedia says that the game was first “unveiled” in 2004 Feb at the All Nippon Amusement Machine Operators' Union and was developed “primarily by Metro, in conjunction with Namco Bandai Games”.
Metro Japan listed the アイドルマスター arcade game among their works with a 2003 copyright by BANDAI NAMCO Entertainment Inc.. This appears to be consistent in terms of the involvement of Metro Japan, Namco, and the 2003 date on the video. Incidentally, the merger of BANDAI and NAMCO to form “Bandai Namco Holdings Inc.” was made in 2005 Sep 29.
@huurai0 contributes iMAS related content to ブロマガ. Their main Table of Contents article for the history of iM@S appears to be this. The title 『アイドルマスター＼ＴＨＥ ＩＤＯＬＭ＠ＳＴＥＲ』was trademarked on 2003 May 8, so all mentions to iM@S prior to this date would’ve likely been simple references to an “idol” game under development. The articles also detail the history of iM@S, including the game being in the 41st Amusement Machine Show (AM Show, 2003 Sep 11-13) prior to release.
アリエスの小部屋 has a report on the 41st AM Show and also mentions iM@S.
The AM Show is open to the public on the 3rd day. Both articles are consistent that videos of the iM@S game in development were displayed even on the public days, although it appears that the iM@S machines were not available. I can’t read Japanese so it’s hard to say if the machines were actually available during the industry/trade days or not. Regardless, the 41st AM Show in 2003 Sep would have been the first “unveiling” of iM@S as a formally copyrighted product, which is consistent with the video.
Where does the 2004 date kick-in? The iM@S machines were available to a limited number of guests during the アミューズメント・エキスポ2004 (AOU2004, Amusement Machine Operators' Union Expo 2004). Perhaps this is why the Wikipedia article considers the first “unveiling” as 2004.
It is worth noting that the original character designer, KUBOOKA Toshiyuki (窪岡 俊之) is also credited in the copyrights from Metro Japan’s listing of the iM@S arcade game. Kubooka is the character designer for other games (like Lunar).
For anime, KUBOOKA was the Animation Director and did the Storyboards for episodes 1 and 2 of the Giant Robo OVA, as well as being one of the Character Designers. He was also the Director for the Berserk: The Golden Age Arc. KUBOOKA was also the Chief Animation Director for ANNO Hideaki’s Gunbuster.
It appears Gainax was a big source of character design talent for the iM@S franchise:
1) KUBOOKA for the original iM@S character designs
The iM@S anime character designs would influence the character designs of the franchise’s future social network games:
[If you want to see the timeline of these items and more, visit my timeline project page.]