The Shinkyokushin system is based on traditional karate like Shotokan and Goju-ryu, but incorporates many elements of combat sports like boxing and kickboxing in kumite.

Many techniques are not found in other styles of karate.

Today, some Shinkyokushin fighters appear in kickboxing events like K-1, but apart from some exceptions, Shinkyokushin does not allow its students to appear in paid fights and remain with the style.

In the past this has caused many high-ranking competitors to leave the organization, even if they continue to practice the art and skills of Shinkyokushin.

In this form of karate the instructor and his/her students all must take part in hard sparring to prepare them for full contact fighting. Unlike some forms of karate, Shinkyokushin places high emphasis on full contact fighting which is done without any gloves or protective equipment. This apparent brutality is tempered somewhat by the fact that you are not allowed to use a non-kick or non-knee strike to hit your opponent in the face, thus greatly reducing the possibility of serious injury. Knees or kicks to the head and face, on the other hand, are allowed.

In the earliest Shinkyokushin tournaments and training sessions bare knuckle strikes to the face were allowed but resulted in many injuries, and, thus, students who were forced to withdraw from training.

Mas Oyama believed that wearing protective gloves would detract from the realism that the style emphasizes. Therefore, it was decided that hand and elbow strikes to the head and neck would no longer be allowed in training and competition. Furthermore, many governments don't allow bare knuckle strikes to the head in sanctioned martial arts competitions. The vast majority of Shinkyokushin organizations and "offshoot" styles today still follow this philosophy.

Technically, Shinkyokushin is a circular style. This is in opposition to Shotokan karate, which is considered a linear style, and closer to Goju-ryu, which is considered a circular style. Shotokan and Goju-ryu were the two styles of karate that Oyama learned before creating his own style. However, Oyama studied Shotokan for only a couple of years before he switched to Goju-ryu where he got his advanced training. This is reflected in Shinkyokushin where the early training closely resembles Shotokan but gradually becomes closer to the circular techniques and strategies of Goju-ryu the higher you advance in the system.