The Light-Hawk Wings (光鷹翼 Koh-Ou-Yoku) are fictional energy constructs from the Japanese anime series Tenchi Muyo!. A source of great power within the series' mythology, they are generated and used commonly by the Jurai Empire's tree ships, but can also be wielded by select characters within the series for reasons explained in the third OVA.
The Light Hawk Wings are primarily a defensive shield capable of repelling almost any attack. They can also be used as an offensive weapon, with great results, but this is not their intended function. Z explains the true nature of the Light Hawk Wings later in the series; they are our universe's manifestations of a higher plane of existence's energy.
The energy required to generate Light Hawk Wings is highly impressive. All Juraian ships can create Light Hawk Wings, though trees from the third and later generations of Tsunami's descendants must join forces to use them.
During the final battle with the villain Kagato, Tenchi discovered that he could control Light Hawk Wings without the assistance of a Juraian tree, and could freely convert this energy into matter: armor, shields, and a sword. With these powers, Tenchi defeated Kagato, and later used them to escape a black hole when he, Ayeka and Mihoshi were trapped inside.
Unfortunately, Tenchi was not alone in commanding the Light Hawk Wings. A mysterious man called Z, who served the Choshin Tokimi, could generate five Wings to Tenchi's three. Z reveals that the three Choshin have been searching for eons, trying to discover a being beyond even them. Tokimi, Washu, and Tsunami each used different methods to continue the hunt, but all three altered the harmony of space and time hoping to cause anomalies that would make the higher power reveal itself. Instances where affected individuals were able to control what we know as Light Hawk Wings were regarded as "potentials".
In Tenchi Muyo! GXP, Seina Yamada inadvertently gained control of Light Hawk Wings when he came into contact with a billion-year-old mecha hidden on a small Wau planet. The mecha was powered by a first-generation Jurai tree seed, and when it bonded to Seina he unleashed the Wings, decimating the fleet sent to kill him and penetrating subspace (which was thought to be impossible) to destroy a fleeing ship.
Besides the Jurai ships (and Seina's mecha), only three characters could use the Light Hawk Wings, Yosho, Tenchi and Z. In OVA episode 13, Yosho and Funaho theorize that, since Ryoko's gems have the same properties as Jurai's trees, Ryoko could use the Light Hawk Wings if she had all three of the gems.
The Light Hawk Wings make a "cameo" of sorts in the anime Dual! Parallel Trouble Adventure, incidentally created by Masaki Kajishima, the man who also created Tenchi Muyo!, a parallel universe to Kajishima's Tenchi continuity.
The robot Zinv was able to form its own Light Hawk Wings after the limiter on its powers was removed. These Light Hawk Wings emerged from Zinv's back, unlike the Wings in Tenchi Muyo! which appear in front of the user. Other than this difference, Zinv's Wings appear to grant the same abilities.
In the non-canon manga, the original English translation of "Koh-Oh-Yoku" was "Lightning Eagle Sword."
In Masaki Kajishima's 2009-2010 OAV series Tenchi Muyo! War on Geminar (Saint Knight's Tale), Kenshi Masaki, Tenchi's half brother who was transported to the alternate world of Geminar is able to generate Light Hawk Wings from his White Sekijin during his final fight against the show's main antagonist Babalun and the Sekishin Gaia (First displayed in OVA 13).