Apex domains cannot have CNAME records.
Question and response
Question
dig atson.jp. NS
Answer
atson.jp. 4 NS dns1.asahi-net.or.jp.
atson.jp. 4 NS crusader.asahi-net.or.jp.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0