Okinawa Giant Stag Beetle

Japanese name: オキナワヒラタクワガタ
Chinese name: 沖繩扁鍬形蟲
English name: Okinawa Giant Stag Beetle
Origin: Okinawajima, Iheyajima, Iejima, Kourijima, Minnajima, Sesokojima, Hamahigajima, Tsukenjima, Tokashikijima, Zamamijima, Akajima, Gerumajima, Kumejima

The giant stag beetle Dorcus titanus is widely distributed across Korea, Japan, Taiwan, China, and Southeast Asia, with 12 subspecies recorded in Japan. The Okinawa giant stag beetle is one of these subspecies, inhabiting Okinawajima and nearby islands. Males measure about 3–6.5 cm, while females range from 2.5–4 cm. Although not the largest among the subspecies, they are commonly seen in forests during summer.

Reference:
https://biodiversity.okinawa/video_pages/reference/okinawahiratakuwagata.html