Take a look at the first Japanese billboard ads featured during baseball.
Our friends at N-Sider have uploaded what is possibly the first 'official' GameCube advert as sanctioned by NCL:

As you can see it is a simple purple backdrop with the violet GC setup along with the NINTENDO GAMECUBE font logo. To the right there is Japanese writing which says "Nintendo GameCube" in katakana and then "Nintendo" in large kanji characters.
Special thanks to IntestineBoy for originally capturing the ads.