After having made modifications to one's own body, this technique launches a detached part of an arm, using it as a projectile weapon. With a small-scale explosion, caused by chakra collected in the cut end of the wrist, the hand portion gains propulsive power and flies off in a straight line with tremendous force. Its destructive power is great enough to easily break through even thick bedrock. The hand portion is protected with chakra, which allows it to remain unscathed. The chakra in the wrist draws the hand back like a magnet, reattaching it again.
The kaiwan (怪腕) in Kaiwan no Hiya can be translated in two ways. The first and most common way is the idiomatic way: "an amazing or remarkable ability". The second way is by translating the kanji directly: "mysterious or suspicious arm", making the name a pun.
This technique utilises chakra like a magnet, which is similar to how chakra is used in Magnet Release techniques.