More than 300 orienteers, both serving, veterans and civilians, have taken part in the latest round of the Military League South.
This is one of more than 25 competitions they have each year in a sport that is also a highly important military training skill.
At Hawley, Surrey, there are five different courses; ranging from the yellow course for novices over 3.5km, to the 9km brown course for more experienced orienteers.
Unlike a simple running race, orienteering is about more than simple speed. Participants need strong map reading skills to succeed and the quality of the map often makes all the difference.
“You need to be able to read a map to know where you are and where you need to be,” said Major Rob Ashton of the Army and UKAF Orienteering Team.
“Physical fitness helps because it is about the man or the lady who can move fastest across the ground.
"And I think you need to maintain a certain level of concentration because the moment you lose your concentration, you become disconnected from the map and you end up lost.”
One veteran competitor is Major (Retired) Colin Dickinson, who has been involved in Army Orienteering for over 30 years – both as a competitor, planner and organiser.
“There’s generally 20 plus major league events each year,” he told Forces News.
“It’s basically every week, Hawley is particularly popular… Because it’s a diverse area. It’s also very quick and the map is of a good standard.”
Amongst those competing was a large contingent from RMA Sandhurst; one of whom – Major Rob Ashton - credits Major Dickinson with the sport’s enduring popularity.
“Orienteering has always been very popular and to be honest it’s down to the hard work of Colin,” he said.
“Orienteering from an officer cadet perspective is crucial.
"If you can run fast and navigate and have that mental agility that orienteering brings to you, it sets you up well for your service wherever you might be – whatever Corps you go into.”
The sport is also noticeable for the generational diversity of its competitors, with some participants barely out of their teens, others in their 80s.
This is early season for the military league, which runs right through until May.
The Royal Signals women and Royal Logistic Corps men were the Army Inter-corps winners last year, but competition is fierce to win the titles in a sport that runs and runs throughout the year.