Chi Ma Wan country trail is easily reachable from the village of Pui O by first walking through Ham Tin and then continuing on the Chi Ma Wan road which is also part of the Lantau trail section 12. The starting point of the trail is on the right hand side at the same place where Lantau trail turns left from the paved road.
If you want to cover the entire trail which zig zags the hills it’s in total 18.5km long. We chose to however only cover some 10km of it which was plenty given that it included a total of some 400m of vertical climbing in extremely humid and hot (+33c) weather. And especially since the climb is mainly steps. But you have 360 degrees view which is totally worth it on the top – or actually the two tops of the hill!
If you want to take the same shortcut as we did, just follow the trail from the starting point with the gate up the two hills (there are no turns so you just follow the trail) until after the second hill you come to a junction where you should turn left. This one takes you past the reservoir and if you always keep going left you eventually end up in the same place you started from. After the reservoir, you can either take the road or the smaller path for which the starting point is hard to spot but you can see it in e.g. google maps.