Joe Tomei here, Just picked up this notice for a "recycle park market" in Shirakawa Park on 22 April (29 April in case of rain). I put this up early in case anyone wants to have a booth (1000 yen for a 2x3 m space). There are more details at their website at https://rpmkumamoto.wixsite.com/rpmkumamoto and perhaps some folks can chime in if they have done this before.