In order to cope with these changes, emerging merchants began to establish za called 'shin-za' (literally, "new za") for the sake of the same privileges as existing za had, and some of them even formed the third form of za called 'mago-za' (literally, "grandchild's za").
それに対して新興商人側も「新座」と呼ばれる座を結成して既成の座と同様の特権を求める動きが現れ、更に「孫座」と呼ばれる第三の座すら現れる例もあった。