Yaƙin Kleidion ya faru ne a cikin kwarin da ke tsakanin tsaunukan Belasitsa da Ograzhden, kusa da ƙauyen Klyuch na Bulgaria na zamani.An yi wannan gamuwa mai tsanani ne a ranar 29 ga watan Yuli tare da kai hari a baya da wata runduna karkashin Janar Nikephoros Xiphias na Byzantine, wanda ya kutsa kai cikin yankunan Bulgaria.Yakin da ya biyo baya ya kasance babban shan kashi ga Bulgarian.An kama sojojin Bulgaria kuma an makantar da su ta hanyar Basil II , wanda daga baya za a san shi da "Bulgar-Slayer".Sama’ila ya tsallake rijiya da baya, amma bayan wata biyu ya rasu sakamakon bugun zuciya, wanda aka ce makafin sojojin nasa ne ya yi sanadiyar mutuwarsa.Duk da cewa wannan alkawari bai kawo karshen daular Bulgaria ta farko ba, yakin Kleidion ya rage karfinsa na yin tsayayya da ci gaban Byzantine, kuma an dauke shi muhimmiyar haduwar yaki da Byzantium.