From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Tenshinhan gathers energy and forms a vaguely diamond-shaped "window" with his hands by keeping the fingers on each hand together, overlapping the index finger on the one hand with the pinky of the other hand and overlapping the thumbs. The object being focused on gets zoomed in on and visualized inside that diamond and Tenshinhan shouts, "Tri-Beam, ha!" while releasing the large yellow beam from their hands. He also has the ability to fire it with one hand as seen when he fires the Tamashii no Kikoho at Nappa after he loses his arm. In addition to being able to kill the target, this attack can easily kill the user because it drains their life energy.
After training with Turtle Hermit, Karin, Kami, and later North Kaio, Tenshinhan perfected the attack as the Shin-Kikoho, which was essentially an "upgraded" form of the attack that allowed him to control and enhance how much energy he put behind it, inflicting even greater damage. The attack formation itself placed the hands in a seemingly awkward position – and it appeared that later in the series the finger tips were touching and the thumbs were the only things that overlap. The attack was extremely powerful. Tenshinhan once used it against Semi-Perfect Cell, and despite the massive gap between the power of Semi-Perfect Cell and Tenshinhan, Semi-Perfect Cell was unable to break through the repeated blasts, though they did not inflict any real damage to him. Tenshinhan eventually collapsed after using the technique too much, but was saved from Semi-Perfect Cell by Son Goku.
Tien Shinhan Saga
Tenshinhan used this attack in his match against Goku at the 22nd Tenkaichi Tournament.
Dragon Ball Z
Perfect Cell Saga
Cell Games Saga
While Cell himself was not seen using this attack (although it was likely that he was able to since he possessed Tenshinhan's DNA) during the Cell Games Saga, the Cell Juniors attacked Son Gohan in his Super Saiyan 2 form with it, although to no avail.
Kikō (気功) is the Japanese translation of Qigong or Chi Kung, literally meaning "breath work" or "energy work", a traditional set of techniques for controlling breathing or circulating and cultivating chi (ki, energy) within the body which is tied to a number of Chinese martial arts and medicinal beliefs.
- Shin-Kikoho - A stronger version of the Kikoho which can be used consecutively. Used against Cell to give No. 18 time to escape.
- Tamashii no Kikoho - A one-handed version of the Kikoho which used Tenshinhan's life force as a source of power. Used as a final resort against Nappa.