The stage was only sixty li, about ten miles, so we really had plenty of time. The Chinese li is of varied length. In this country, where man and beast carry heavy burdens, the payment is calculated by gradient, not yards. Uphill, the li is shorter than downhill. On the level it is of yet a different length. There is a good deal to be said for the plan. A coolie carrying a load uphill from Y to Z is automatically paid more than a coolie carrying the same weight downhill from Y to Z.
Through the narrow ravine we mounted steeply, then dropped again to river level. The road now coasted along through pleasant glades of walnut trees beside the stream, tossing and brawling its noisy way west over enormous boulders.

Neville Bradley, “The Old Burma Road”, London 1946