The campaign belonged to the wider Austro-Russian-Turkish War of 1735 to 1739, and the man who led the Russian effort was Field Marshal Burkhard Christoph von Munnich, a German-born officer in the service of the Russian crown. His enormous force advanced in three divisions across the open steppe toward the coast. Waiting behind the fortress walls stood an Ottoman garrison of some 22,000 infantry and cavalry under the command of Serasker Yahya Pasha, with a commandant named Mustafa and an artillery park of nearly a hundred cannons, seven mortars, and a single howitzer. The two forces were unevenly matched in numbers, but the defenders held stone walls and the attackers had to cross open ground, and everyone on both sides knew what a siege on this coast in high summer would cost.

The first Russian attack broke against the walls and fell back bloodied. Rather than repeat it, the besiegers turned their mortars on the fortress and let the fire do the work. Flames caught somewhere inside the crowded compound and spread fast, and on the second day they reached a powder magazine. The explosion killed roughly six thousand defenders in a single moment. The fortress moved to surrender almost immediately, yet in the chaos that followed, many of those trying to give themselves up were cut down anyway. Of the entire garrison, only around three thousand survived. The dead lay in such numbers, and the summer heat worked so quickly, that the stench forced the victorious Russians to pull their own camp back some fifteen miles from the walls they had just taken. There is no way to tell this without grief: most of the people inside those walls did not fall in the fighting at all.

For all the horror, the conquest proved fleeting. Disease is often the true victor of a siege, and it came for the occupiers as surely as it had haunted the besieged. Late in 1738, an epidemic swept the Russian garrison holding the ruined fortress, and the toll was staggering, with sources recording as many as sixty thousand dead across the wider effort to hold the position. The Russians razed what was left of Ozi and marched away, abandoning at appalling cost a prize they could not keep. The fortress would not be seriously attacked again until a failed siege in 1771, and Russia would only take the strait for good in December 1788. The events of 1737 remain a stark reminder that on this contested coast, holding the gate to the rivers was often as deadly as taking it.