Key

Tenchi muyo 02 Ayeka asleep with sword — Ayeka asleep wearing her tiara on her forehead and holding Yusho's sword in her hand^[1]

A key (鍵, Ken) is an item that helps a person access "the true power of the planet Jurai" through a Royal Tree. It helps bond the user (usually members of the Juraian Royal Family) with a tree, not allowing any one else to use it without permission. The key is made by processing the sap from one of the branches of a royal tree, then converting it into jewelry or other shapes. The key assists in accessing the Light Hawk Wings, the most powerful force in the universe.

Master Key

A master key (マスターキー, Masutaa Kii) is created from the first generation Royal Trees and have the power to control all treeships. First generation keys can harness the exceedingly powerful Light Hawk Wings in order to create a light sword (ex: sword Tenchi), while the keys of younger trees can't.

Tenchi-ken

Main article: Tenchi-ken

Tenchi-ken (天地剣, Sword of Heaven and Earth), or Sword Tenchi, is a master key used for Funaho, the first generation Royal Treeship who is bonded to Prince Yosho. Tenchi-ken is a very powerful master key and has the ability to control most royal tree ships. When Prince Yosho trapped space pirate Ryoko in the Masaki Shrine, he took her three gems, created by the Chousin Goddess Washu, and placed them on the pommel of the sword. The gems gave power to Funaho because they come from a similar power as the trees (the trees were created by Tsunami, Washu's sister) allowing Yosho to retain his youth (though to others, he appears as an elderly man). The sword can only be used by someone of noble Juraian blood, and used to be Tenchi's most powerful weapon until his ability to generate the great Light Hawk Wings surfaced. The sword is said to have been carved from a branch of the first Royal Tree, Tsunami-no-ki.

Normal Keys

Normal keys (ノーマルキー, Noomaru Kii) are keys made from trees that were grown after the first generation of trees. The keys can create Light Hawk Wings as a defense mechanism for the person, but they cannot create a light sword. Master keys are far more powerful and can bypass normal keys.

For example: Princess Ayeka has a normal key through Ryu-Oh, a second generation tree, in the form of her tiara.