Once a great enemy army invaded Kachu. The people of Kachu met the attackers resolutely and gave them no chance to take the fortress. The enemy then found the spring from which the defenders drew their water and cut off the channel. The people of Kachu found an ingenious way out of this plight: they took a tkhori (a great ball of wool yarn), lowered it into the Arghuni, then wrung it out and obtained enough water to drink. Hence the fortress's second name — Tkhorus Tsikhe