% APNIC found the following authoritative answer from: whois.apnic.net

% [whois.apnic.net]
% Whois data copyright terms    http://www.apnic.net/db/dbcopyright.html

% Information related to '2400:4000::/22'

% No abuse contact registered for 2400:4000::/22

inet6num:       2400:4000::/22
netname:        OCN-JPNIC-JP-20050815
descr:          Japan Network Information Center
country:        JP
admin-c:        JNIC1-AP
tech-c:         JNIC1-AP
remarks:        JPNIC Allocation Block
remarks:        Authoritative information regarding assignments and
remarks:        allocations made from within this block can also be
remarks:        queried at whois.nic.ad.jp. To obtain an English
remarks:        output query whois -h whois.nic.ad.jp x.x.x.x/e
remarks:        *****************************************************
remarks:        For abuse/any contacts regarding this address range,
remarks:        please refer to the contacts listed on the inet6num
remarks:        object displayed down below, or look up JPNIC Whois.
remarks:        ****************************************************
mnt-by:         MAINT-JPNIC
mnt-lower:      MAINT-JPNIC
status:         ALLOCATED PORTABLE
last-modified:  2008-09-04T06:49:19Z
source:         APNIC

role:           Japan Network Information Center
address:        Uchikanda OS Bldg 4F, 2-12-6 Uchi-Kanda
address:        Chiyoda-ku, Tokyo 101-0047, Japan
country:        JP
phone:          +81-3-5297-2311
fax-no:         +81-3-5297-2312
e-mail:         hostmaster@nic.ad.jp
admin-c:        JI13-AP
tech-c:         JE53-AP
nic-hdl:        JNIC1-AP
mnt-by:         MAINT-JPNIC
last-modified:  2022-01-05T03:04:02Z
source:         APNIC

% Information related to '2400:4000::/22'

inet6num:       2400:4000::/22
netname:        OCN-CIDR-BLK-JP
descr:          NTT COMMUNICATIONS CORPORATION
remarks:        Email address for spam or abuse complaints : abuse@ocn.ad.jp
country:        JP
admin-c:        JP00009614
tech-c:         JP00009427
remarks:        This information has been partially mirrored by APNIC from
remarks:        JPNIC. To obtain more specific information, please use the
remarks:        JPNIC WHOIS Gateway at
remarks:        http://www.nic.ad.jp/en/db/whois/en-gateway.html or
remarks:        whois.nic.ad.jp for WHOIS client. (The WHOIS client
remarks:        defaults to Japanese output, use the /e switch for English
remarks:        output)
last-modified:  2019-02-20T22:26:42Z
source:         JPNIC

% This query was served by the APNIC Whois Service version 1.88.25 (WHOIS-AU2)

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