Once again we return to the wild and crazy cosplay x internet video x music event called “Niconico Chokaigi” We did brain waves again like 2016, although this year we had a special session where one of the performers from 2016, IshiHanaKai (Stone Flower Club : Rock Balancing Art), came to center stage for a brain wave battle. We measured the concentration of the two rock balancers as they had a balance-down on stage. We also measured the weight of the rocks in real time to give an idea of what they were working with.