Battle of Mustafa Achi and Azaplar

The battle took place during the First World War between Bulgarian and Romanian soldiers. Romanian troops advanced into Bulgarian territory against the right flank of the Bulgarian Third Army. The battle itself occurred when the 1st Cavalry Division, led by General Ivan Kolev, came to the Third Army's aid and intercepted the Romanian infantry. The engagement aimed to defend the lands of Northern Dobruja and stabilise the Bulgarian front there. 

After the unsuccessful attack against the Third Army's forces near the Danube on 21 September and the failed mass offensive against the positions at the southern end of the Bulgarian line, the enemy continued to strengthen its forces against the Third Army's right wing. The Third Army command deployed the Turkish 25th Division, the Cavalry Division and units of the March Brigade to prevent a breakthrough on the flank. In the following days, successful defensive actions and counterattacks against the Russian–Romanian troops prevented the enemy from carrying out its tactical plan.

Russian cavalry occupied Gelendzhik, present-day Pobeda, and Perveliya. The Cavalry Division's advance guard drove the Russian squadrons out of Gelendzhik after stubborn fighting. The Turkish 25th Division, supported by batteries of the Dobrich forces, launched a rapid attack and drove the enemy north of Amuzacha. Because enemy activity was limited, the army's right wing moved north on 24 September, where favourable terrain secured Kazichi station on the Varna–Dobrich–Kara Yumer railway.

Following the unsuccessful attempts to dislodge the Bulgarian forces, quiet prevailed along the entire front from 25 September to 1 October. The enemy failed to seize the initiative and reverse the course of operations. The Bulgarian army firmly established its positions before the enemy's heavily fortified defensive line between the Black Sea and the Danube.