The recent Corda 15th anniversary Songs event is available for purchase (members only) through the Game City online store. It’ll come in two flavors: limited (with a variety of extras)and regular (no extras at all).

Details
DVD: Corda Songs
Format: 4 DVDs (regular edition), 4 DVDs + CD (limited edition)
Extras: (limited only) Back stage footage (on disc 1), music CD of instrumentals, booklet, can badge set & tapestry (Len + Kyouya). Plus a Game City only extra: cleaner cloth featuring Len & Kyouya
Release Date: 6/5/2019
Price: 9,000 / 18,000 + tax
Details: Gamecity store