Whenever one or more creatures you control attack, each defending player divides all creatures without flying they control into a "left" pile and a "right" pile. Then, for each attacking creature you control, choose "left" or "right." That creature can't be blocked this combat except by creatures with flying and creatures in a pile with the chosen label.
![Raging River [Collectors' Edition]](http://tothetablebgc.myshopify.com/cdn/shop/files/9c118b97-1e50-4fd1-816d-a63a4128d539.png?v=1776445503&width=1445)
