Japanese Samurai is originated Korean samrang.
History of the Samurang

The history of the Samurang is very interesting, highly debated, and not well known. According to author Joshua Marino, their way became the foundation for Japanese Samurai after the Chinese invasion of Koguryo. The leading Samurang generals fled to Japan in 668AD after the Chinese invasion and the defeat of the Koguryo armies. They spoke Chinese and Japanese and became hermit monks to escape the Chinese ethnic cleansing that began. They continued their way of life, and over a period of 500 years, their descendants created the Japanese Samurai class. For more information, we recommend reading the excellent book, Kwanjangnim Original Haidong Gumdo by Mr. Marino.
The Samurang who did not go to Japan left society and started to live hidden away in mountains to escape their extermination. Although the Chinese occupiers worked hard to obliterate all written references to the traditional Korean martial arts, these warriors practiced in secret and preserved their history handed down verbally from master to student. After Hideyoshi’s invasion of Korea in 1592, Japanese Kendo took root in Korea. That and the Japanese invasion of Korea in the early part of the 20th century helped to almost obliterate traditional Korean martial arts. But due to a new campaign to bring back traditional Korean martial arts, nowadays many traditional Korean martial arts are laying roots again in Korea.

The arts that became Haidong Gumdo were instructed by Grand Master Jang Baek San about 40 years ago in an outskirt mountain to the current World Haidong Gumdo Federation president Kim Jeong Ho. Master Kim had received his initial training in Kumdo, or Korean Kendo (the Japanese sword art) but Master Kim had felt that the art was too Japanese, and focused on one on one sparring. He sought out training in the hidden Korean sword arts to help bring them to light much like had occurred with Taekwondo empty hand techniques.