Genome editing technologies have been invented and improved in recent years, and there is a growing expectation that the technologies can be utilized as a tool not only for molecular biological studies, but also for genetic therapies. Among them, CRISPR‐Cas9 system that was originally found as a part of the bacterial adaptive immune system gets noticed for its easy introduction. Here, users are only required to design a guide RNA with a 20‐nt sequence that is complementary to the target DNA sequence and co‐express Cas9 with the RNA in vivo , then Cas9 protein will cleave the target DNA in a site‐specific manner. This is a portrait of a kabuki actor who plays Cas9 as indicated by the crest “ku” (‘nine’) on kimono he is wearing. The “actor” definitely has a promising future ahead of him. Designed by TRAIS Co., Ltd. (Kobe, Japan)