Kailash Express, by Air and Helicopter

Because it avoids the drive across the plateau. The overland routes spend four days crossing western Tibet by road from Kerung or Lhasa. This route flies to the far north-west of Nepal, crosses the border by helicopter, and reaches Taklakot, twenty kilometres inside Tibet, on the fourth day. The approach is a fifth of the distance.

Less time to acclimatise. On day three you sleep at 150 m in Nepalgunj. On day four you sleep at 3,900 m in Taklakot. This is a larger gain than any doctor would recommend, which is why day five is a compulsory rest day. This route suits travellers who are fit, who have been to high altitude before, or who have time to arrive in Nepal early and trek first.

Overland by road in both directions takes sixteen days and is the easiest on the body. The route via Lhasa takes fourteen days and includes the monasteries. The route via Beijing is the most comfortable and the most expensive. This trip takes eleven days and is the most difficult for acclimatisation. It is designed for pilgrims who cannot take three weeks away.

Anyone who has had altitude sickness before, anyone over seventy without a recent high-altitude trip, anyone with heart or lung disease, and anyone who has never been above 3,000 m. This is not about fitness. It is about how quickly this itinerary gains height, and the overland trip is more suitable in all these cases.

Delays are common enough that we include a spare day for them. Simikot has a 549 m runway at nearly 3,000 m, and aircraft fly only in clear, calm morning conditions. Delays of one to three days happen every season, in both directions. Most trips lose no time. Some lose a day, and a few lose more.

We provide your food and accommodation and immediately start arranging your onward flight. The itinerary includes one spare day for this. After that day, extra nights and any change to your airline booking are at your own cost, which is why we ask everyone to book an international flight that can be changed and to take out insurance for travel delay.

Yes. A 51 km road and bridge were built from Simikot to the border in 2016. The road is rough, slow and prone to landslides, and the journey takes most of a day each way. We use the helicopter because it takes twenty minutes and because the road is not reliable during the season.

The limit is strict. The Simikot aircraft and the helicopter allow about 15 kg of checked baggage and a small daypack. Anything over the limit either stays in Nepalgunj or travels on a later flight if there is space. Pack for eleven days within the limit and leave everything else at your Kathmandu hotel, free of charge.

The kora takes three days and covers 53 km, the same circuit that every Kailash pilgrim walks. The first day is twelve kilometres and gentle. The second is twenty-two kilometres over the Dolma La at 5,630 m, takes nine to ten hours and is very demanding. The third is twelve kilometres downhill and ends before lunch.

On the first and third days, yes. A horse with a handler is arranged at Darchen for about $180 to $260. On the pass day, a horse can take you only as far as the terrain allows, and everyone walks the steep section above Shiva Tsal. Decide the evening before, because the horses are allocated in turn.

You return to Darchen with a crew member and rejoin the group when it completes the circuit. This decision is made at Dirapuk in the morning, before the pass, not partway up it. Nobody is carried over the Dolma La, and on this route in particular we prefer that someone stops early rather than continues.

We include a rest day at Taklakot, measure and record your oxygen saturation twice a day, carry bottled oxygen and a portable pressure chamber with the group, and your guide's instruction to descend is final. We also take you down to Taklakot at 3,900 m as soon as the kora is finished, rather than keeping you at altitude for another night.

No, and this is especially important on this route. There is no helicopter evacuation anywhere in Ngari. Descent means travelling by vehicle and road, back the way you came, and the border at Hilsa may not be open at the time you need it. Your insurance must cover evacuation to 6,000 m, and we check your policy.

Ask your own doctor, early enough to try it at home first. Because this route gains height quickly, more travellers take it than on our other Kailash trips. It does not replace the rest day, drinking enough water, or telling your guide as soon as you have a headache.

The same four permits as any Kailash journey: a Tibet Travel Permit, an Alien's Travel Permit, a military permit and a foreign affairs permit, all arranged by us. In addition, you need the Chinese group visa issued in Kathmandu, which takes four working days and requires a group of at least five travelling together.

At least eight weeks. The Tibet Travel Permit takes eight or nine working days once the itinerary is paid for, and the Kailash area permits are issued in Ngari on their own schedule. With the group visa and the Simikot flight, which sells out in the season, two months is the realistic minimum.

From May to September. Outside these months the Dolma La has snow, the kora guesthouses close for the winter, and Tibet usually closes to foreign visitors for the whole of March. On this route, the Simikot flights are most reliable in the clear weeks of May and September.

Hotels in Kathmandu and Nepalgunj, a simple hotel in Taklakot with heating and hot water, a lakeside guesthouse at Mansarovar, and two nights in kora guesthouses at Dirapuk and Zuthulpuk. The kora guesthouses have shared rooms with a mattress and quilt, no heating and an outside toilet.

Vegetarian throughout, as is customary around the mountain. Dal bhat and Nepali food as far as Simikot, Tibetan and Chinese food beyond, and our own cook carries supplies for the kora. Appetite decreases at altitude, so we serve soup first and often, and make sure nobody skips a meal.

In the hotels, yes, using a Chinese adaptor after the border. At Mansarovar and on the kora, no. Your Nepali SIM card stops working in Tibet, Chinese SIM cards have no coverage on the kora, and many common apps are blocked in China. Bring a battery pack and keep it inside your jacket, because the cold drains batteries quickly.

Wind protection is more important than extra warmth, because the wind on the plateau is constant and dry. A four-season sleeping bag for the two kora nights. More sun cream and lip balm than you expect to need. A change of clothes in your daypack, because if the helicopter is delayed your duffel bag may be on a later flight.

If this happens before departure, we refund everything you have paid us, and where dates allow we offer you the overland trip instead. If a border closure leaves the group inside Tibet, we bring you out through the other crossing at our own cost.