According to the All Japan Jukendo Federation, "Tankendo means the 'Way of the Short Sword'. It is a budo allied to jukendo that is based on traditional Japanese kodachi (short sword) techniques.
Tankendo is very similar to kendo, with only a few differences: – practitioners use a 53cm short shinai – practitioners also use the same armor as in kendo, but wear only the right kote, and the urabuton under the right armpit – targets in tankendo are the same as those in kendo, with the addition of a thrust to the torso (dō-tsuki) and a close quarter thrust to the torso after arm-locking the opponent (seitai-zuki)
Jukendo and tankendo competitive matches are known as shiai, in which competitors wear protective armor and try to score two out of three valid points (sanbon shōbu). Children also take part in matches in which the quality of fundamental techniques or kata proficiency are judged.
Jukendo and tankendo are practiced in Japan by men and women alike, children and seniors."
The dress for tankendo involves the same the same dōgi used in jukendo.
Samurai referred to the Kodachi as the smaller of of the two swords, together known as daisho, that was worn at the waist. The Kodachi is the weapon used in modern tankendo.
Tankendo is derived from the spirit and technique of Kodachi, in view of the particular results of the first World War. The old Toyama school researched dagger usage, which culminated in the birth of Tankendo in 1921.
Originally Kodachi practice had its roots in the Kodachi of Nakajo-ryu, which is also said to have been one of the three large styles in Japanese kendo, as well as the Kodachi tradition of Tomita-ryu, which was also famous. Modern Kodachi practice, "Japan Kendo shaped" which was enacted in 1912 Kodachi left behind these three of styles of usage.
(This section has been roughly translated from the Japanese Federation website and is in need of cleanup)