Author's Reply to Oka and Colleagues. Issue 1 (9th January 2018) - Nagai, Kojiro; Tsuchida, Kenji; Ishihara, Noriyuki; Minagawa, Naoto; Ichien, Go; Yamada, Satoshi; Hirose, Daisuke; Michiwaki, Hiroyuki; Kanayama, Hiro‐omi; Doi, Toshio; Minakuchi, Jun