Apex domains cannot have CNAME records.
Question and response
Question
dig tocn.ne.jp. NS
Answer
tocn.ne.jp. 4 NS nocsv001.tocn.ne.jp.
tocn.ne.jp. 4 NS nocsv015.tocn.ne.jp.
Authority
The response has no authority records.
Additional
nocsv001.tocn.ne.jp. 4 A 210.175.192.3
nocsv015.tocn.ne.jp. 4 A 210.175.192.6
nocsv001.tocn.ne.jp. 4 AAAA 2001:3c0:0:2:0:0:0:3
nocsv015.tocn.ne.jp. 4 AAAA 2001:3c0:0:2:0:0:0:6
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0