Each of the gates of Derbent is unique; none of them are repeated or resemble other Derbent gates. Among the most famous gates of the Naryn-Kala citadel are the western gates, or as they are officially called, Dag-Kapy (10th century). But the Dag-Kapy are truly special. Architecturally, the gates are modestly decorated and are more filled with practical meaning. There are almost no decorative ornaments. Standing directly in front of the gates, there are no small details that invite closer inspection. At first glance, it looks like ordinary masonry and poor architecture.

These are the second gates directly into the Naryn-Kala citadel. They are located on the opposite, western side of the fortress. Beyond the gates begins a mountain road that led deep into the Caucasus mountain range.

By their primary purpose, the gates served for the entry of horse-drawn transport, horned cattle, pack caravans, and so on into the citadel. That is, they carried an economic function.

Dag-Kapy can be translated as "mountain gates" since they opened onto the mountains. This is what the local population called them. From the fortress to the village of Khuchni, about forty kilometers away, ran the mountain wall called Dag-bary. During a siege of the city, under the cover of this wall, reinforcements could enter the city through the Dag-Kapy gates.

For this reason, the mountain gates were designed to allow complete control over everyone beneath them. The opening is 3 meters wide. The gates have two flanking protrusions, each 8 meters long. The walls of these protrusions are sloped, which prevented the enemy from hiding beneath them, and the defenders did not need to expose themselves to shoot at them. The walls are high, up to 10 meters, with conical loopholes.

Behind the gates is a small clearing, and beyond it, a cliff. The flanking protrusions continue as a high wall with loopholes. In general, an enemy on this well-visible clearing would be like on a hot frying pan.

On the inside, everything is also arranged to prevent enemy penetration into the city. From the very gates, the road into the fortress goes uphill. If the enemy penetrated, they would have to run uphill, which is more difficult. On both sides of the road, inside, there are again flanking protrusions. At first, they are 2 meters high and gradually decrease. This is also an advantage for the defenders. Above the gates is a platform from which it is convenient to attack on both sides of the gates.

In peacetime, all these tricks had no significance, but in wartime they could play a decisive role.

Among the people, they were called mountain, secret, spare, and even gates of fugitives or shame. The reason is that one of the rulers of Derbent retreated through these gates during a battle, surrendering the city to the enemy. Because of this, these gates were not used even in peacetime, as exiting through them was considered disgraceful. When in 1722 Peter I inspected the fortress and was told the story of these gates, the emperor decided to exit through them no matter what. He was once again explained that this was inappropriate. However, Peter I, saying "What do I, the Russian tsar, care about Muslim shame," still went out through them, thereby lessening the degree of shame.

Sources:

https://welcomedagestan.ru/placepost/vorota-dag-kapy/

https://pro-derbent.ru/dag-kapy