The Ridgeway Furrows

The approach

Park at the Ridgeway car park above Letcombe Regis, where the byway leaves the tarmac and turns to chalk and flint. The gate at the top is the start. From there you are on the National Trail proper, walking north-east with the Vale of White Horse falling away on your right and the beech hangers on your left.

The first half mile is level and dull, which is a trap: people rush it and then arrive at stage one already warm and annoyed. Take it slowly and look right. That slope is where the puzzle is.

Stage one: read the ground

The published coordinate puts you at a gatepost on the parish boundary. Look east across the field and you will see the land rippled in long parallel waves, roughly four to six metres from crest to crest, running across the slope rather than up it. That is ridge-and-furrow: the raised strips are the ridges where the plough heaped soil, the hollows are the furrows that drained it. It was dug by ox teams on heavy clay before the Black Death, then abandoned when the population fell and marginal land stopped being worth ploughing.

Count the ridges between the gatepost and the lone hawthorn on the skyline. That count is the first half of your offset, and it will be between eight and fourteen — if you get something outside that range, you are counting the furrows instead of the ridges.

Stage two: the arithmetic

From the gatepost, walk the number of ridges you counted in metres along the bearing 042°. That puts you at a second post, this one a squat concrete strainer with a hole drilled through it. Inside the hole, rolled tight, is a strip of paper with the offset for the final: north plus 0.00412, east minus 0.00718, applied to the published coordinate.

Do it on your phone if you like, but check it: the classic error is to add the north offset to the wrong decimal place and end up four kilometres away in Wantage. Rough sanity check — the final should be within 700 metres of the published point and still on the chalk.

What you are looking for

A 200ml screw-top container, wrapped in a length of faded green webbing, tucked into the base of a beech where it meets a chalk bank. The beech is the only one on that stretch with a trunk that forks at head height.

Where people go wrong

• Counting furrows as ridges. On a slope this shallow the furrows read as the more obvious feature, and you will be out by a factor of two.
• Doing the stage two arithmetic on a phone in the wind and misreading a minus sign. Write it down.
• Coming at this from the village. The footpath from the bottom is a leg-burner and lands you at the wrong gate with no view of the furrows.

After the find

The National Trail continues north-east to Wayland's Smithy, a Neolithic long barrow under beech trees about two miles on. It is a better destination than the cache. If you have time, drop south off the ridge into Letcombe Valley nature reserve, where the spring line feeds a chain of damp meadows.