The 2014 LP Central Asia swiftly mentions Kojo Kelen and a trek to Sary Moghul over the Jiptik pass. We are very glad they mentioned it but I have not found alot of info on the internet about it so I want share our experience.
We chartered a taxi at the bus station in Osh for 2500 som to Kojo Kelen (CBT can arrange it for 3000). There was a mashrutka going at 13h30 but it would arrive to late to start the trek. The taxi ride is about 3.5 hours through very nice landscape and cirkels through the mountains until it reaches the very pituresk village of Kojo Kelen. It is a very rural village surrounded by red sandstone and white sandstone cliffs in the background.
To start the trek, follow the main road on the right side of the river through the village. Keep on following this road for about 4-5 hours, the road is always near the river, where you can set up camp on the riverbank. We hiked for 4 hours and did just that near the very last small hut of a sheperd. The next day, try to start early, the road will go up for 5-6 hours and an elevation rise of about 1500m-1800m to reach the top of the Jiptik pass. This route is very beautiful and shows a constant backdrop of craggy peaks, where between them lies the Jipitk pass. The route is still the same one and is very straightforward even at the pass itself (CBT claims it dissappears but i guess this only happens when it snows). After reaching the peaks try to go down for at least 2 hours to reach decent camping grounds. Try to take the road which is closest to river at all times. We reached a riverbank just before the route goes through a canyon. A bit further (20min) CBT has a yurt set up. The next day you can reach Sary Moghul in 3 hours with the constant view of the mighty peak Lenin and his big friends :)
The trek is quite hard on the second day but if you are reasonably fit and have some moutain experience you can surely manage. You can do it yourself completely (try to get a map or a copy in CBT Alay in Osh) if you have all your camping stuff.
This has definitly been the best trek we did in Central Asia untill now and maybe one of the most beautiful and rewarding ones I have ever done.
Happy hiking!

