A hill fort is best read from its gateways upwards

The hill did most of the fortifying before anybody built anything

The first thing to understand about a hill fort is how little of it is wall. A steep-sided hill is already an obstacle, and the builders’ job was to close the few places where the slope was climbable, not to ring the whole summit in masonry.

That is why the defences of a large fort look so uneven. One flank may carry two or three lines of rampart with bastions every few dozen metres, and the flank round the corner may have nothing at all, because the rock there falls away and nothing was needed.

Where the natural slope was almost good enough, it was improved. Scarping — cutting the rock back to a vertical face for a band below the wall — appears constantly in Deccan forts, and a scarped hillside is easy to spot once you know to look for a smooth grey stripe running horizontally under the ramparts.

The gateway is where the design becomes visible

A gate is the deliberate weakness in a defensive system, and everything interesting happens around it. The classic Indian solution is to make the approach turn: the path arrives along the base of the wall so that anybody on it has their unshielded side exposed, then bends sharply immediately before the opening.

That bend has a second purpose. A straight run allows a battering ram or an elephant to build momentum, and a right-angled approach removes the run-up entirely. The heavy iron spikes set at chest height on the doors of many north Indian and Deccan forts are addressing the same threat from the other direction.

Above the gate there is usually a projecting balcony or a row of openings in the ceiling of the passage. Both exist so that the defenders can act on whatever is standing in the entrance, and a passage with several sets of doors in sequence turns the gateway itself into a trap rather than a doorway.

A fort was a settlement, not a building

Inside the walls of a substantial fort there was a garrison, a court or governor’s residence, granaries, magazines, stables, workshops, temples or a mosque, and often a resident civilian population. Many of these places held several thousand people and functioned as the administrative centre of a district.

That is why a large hill fort takes a full day rather than an hour. The ruins are spread over the whole summit plateau, the paths between them are rough, and the interesting structures are frequently the plain ones: a granary with ventilation slots, a magazine cut into rock, a set of grain-grinding stones.

Water was the constraint on all of it, and the reservoirs and cisterns you will walk past were the difference between a fort that could hold out and one that could not. It is enough here to notice how much of the summit is given over to catching and storing rain.

There are several fort countries and they do not look alike

The desert forts of Rajasthan are the ones most visitors picture: enormous curtain walls in yellow or red sandstone, elaborate palaces inside, and towns that grew up at the foot of the walls or, at Jaisalmer, inside them.

The Sahyadri forts of Maharashtra are a different tradition altogether — hundreds of them, mostly small, sited on basalt spurs above the Konkan and the plateau, and often reached by steps cut into the rock. Many have very little standing masonry left and are visited as walks rather than as monuments.

The Deccan sultanate forts are the third kind, and they were built for artillery. Round bastions with sloped bases to deflect shot, thick low walls rather than tall thin ones, and gun platforms at the corners: Golconda and Bidar show the shift clearly, and it is the same military logic that reshaped European fortification in the same centuries.

Climbing one is the visit

The approach is normally a long stair or a steep track with no shade, so a fort is a morning or a late-afternoon proposition and a bad idea in the middle of a hot day. Carry water up; there is rarely any at the top, and where a summit does have a stall, do not plan around it.

Many forts are unmanaged, which is part of their appeal and also the risk. Ramparts have unguarded drops, cisterns are open, steps are worn smooth, and after rain the rock and the grass on it are both slippery. Footwear with grip is not optional on basalt.

Whether a particular fort is a protected monument with staff and set hours, a state-managed site, or simply a hill anybody can walk up varies enormously, and so do rules on drones, on camping and on access to particular structures. Check the position for the specific fort before going, because the answer changes from one hill to the next.