Bring the delivery notice and personal ID to the Minoh post office to pick up your item.
https://www.post.japanpost.jp/int/ems/ryugaku/intl_student/index_en.html
Refer to the link below:
If you want to send printed matter to yourself, when the sender and recipient are the same, you can use 国際郵便 特別郵袋印刷物 (special mailbag printed matter). However, you have to bring your books and/or stack of paper to 大阪北郵便局 (Osaka Kita Post Office) or 大阪中央郵便局(Osaka Central Post Office). They won't pick up your books at your apartment. The maximum weight in one bag is 30 kg. For example, the shipping charge to New York in the USA by air at 30 kg is 42,450 yen, and by ship
15,950 yen. You can choose any of air, SAL, and surface.
https://www.post.japanpost.jp/int/service/s_printed_matter.html