Board Thread:General Discussion/@comment-25884981-20150902160808/@comment-24801399-20150902161830

Haiku Day was simply a mascot meetup for Sensei (since he has not appeared at a party since mid-2013) and they decided to name it for whatever reason.

Also, this really does not "reveal" anything... simply just CP asking for feedback. Shadow is extremely unlikely too, as Polo Field said earlier this year that they want to rework the original Card-Jitsu, and then get the original, fire, and water to mobile, all before even starting shadow. So it is highly unlikely we will see it any time soon.