The Mount Rinjani Ultra trail race is arguably the best known Indonesian race on the calendar, and not only because of the outstanding views on the summit of the 3726m high volcano, but also because of the DNF numbers in the first two editions of the race. The climb up and descent of the volcano is tough - there's no other word for it with over 5500m elevation gain in 52km - and combined with the tropical climate and high altitude makes this a challenge for every single participant.

Last year only 22% of the 212 starters managed to complete the 52km race within the cut-off time of 22 hours! This year even more people will try and complete this feat, and score Asia Trail Master points in the process. Mount Rinjani is one of these iconic volcanoes in the world, which has become a popular destination for adventurous trekkers. It sits high on Lombok, a small island to the east of Bali. Views on the summit are breathtaking and make for popular computer wallpapers.

Participants this weekend an also take part in our Instagram competition to win a free race entry to the Bromo Tengger Semeru event in East Java from 6 to 8 November. To have a chance to win, runners need to submit a photo of themselves wearing an Asia Trail Master gadget using the hashtag #asiatrail and the @asiatrailmaster mention.

Mount Rinjani Ultra, organised by FOneSport and its Indonesian trail running hero Hendra Wijaya, is the second of four Indonesian races on our 2015 calendar. The first race, Gede Pangrango Marathon near Jakarta in West Java, was won by local runner Jumardi. Later this month there is also a 2016 Candidate Race, the Ijen Trail, on 22 August, and then there is Mesastila Ultra Challenge on 10 October and Bromo Tengger Semeru in November.

Epic trail race on Lombok's Rinjani volcano