According to the tweets, a logo for the anniversary (shown on the left) and a background design for goods (shown on the right) have been created thus far.

What’s interesting to note is the usage of Sumo Stickers in the second image. Sumo Stickers of unknown origins began to show up in several locations throughout Japan in 2009, about one year after the release of the original Chaos;Head. As such, Sumo Stickers are never mentioned in Chaos;Head, or in Chaos;Head Noah. In Chaos;Child, Sumo Stickers play a major role in the plot, so it’ll be interesting to see how the stickers will be used in relation to Chaos;Head.

Here are some examples of the real life Sumo Stickers, dating back to 2009.