Climbing on limestone. I’ve only tried it once before, in Switzerland. During a trip to Interlaken in 2012 I met up with a Swiss guy called Davide. He was a better climber than me and knew the area, which was ideal. We decided to head to the 200 metre tall limestone wall at Hintisberg, aiming for something at about f6a. For a six-pitch climb, that was at about my level. However thanks to our inept misinterpretation of the topo we ended up on a route called Zick-Zack instead, which was an f6b and was a bit too technical for me. So I ended up seconding five of the six pitches, though luckily Davide was completely happy about it.
It was great, and it taught me two things about limestone. First, limestone is smoother and much less forgiving on sweaty hands (and believe me, I had sweaty hands that day) than the grippier gabbro, granite, schists and psammites I’m used to in Scotland. Chalk is a necessity. Second, finger pockets may be plentiful but only help if your arms aren’t totally pumped out after two pitches!
Fast-forward four years. Limestone is a water-soluble material and is easily dissolved by acid. The resulting solution can be redeposited elsewhere, which leads to its weird and wonderful forms. The rock literally melts and then re-forms like candle wax. Nowhere is this more obvious than Ton Sai, Thailand, where I recently spent the New Year and the first few days of 2016 with my girlfriend Marie. A small climbers’ village, Ton Sai sits surrounded by an immense limestone amphitheatre. The only way to get there is by longtail boat. Towering walls stretch vertiginously upwards all around it, their sunbleached shades of white and cream blending into yellow, orange and coffee-stained tufa. The stalagtites alone are something else. Fluted and warty, they cling precariously from the cliffs all around Ton Sai and often grow to metres in length.
Ton Sai is a climber’s paradise, with more than 700 bolted routes over about 50 crags, plus offshore deep water soloing for when you want to get salty. I tried my hand at a number of crags over my two visits (I was also there in the second week in January) and found it excellent. From a standing jump-start onto a low hanging stalagtite at 123 Wall, to incredible exposure and stunning views over an emerald bay from the well-named Lord of the Thais (first pitch, 6a+), Ton Sai was amazing. The limestone is strange stuff though. Sometimes it seems purpose-built for climbing, with near-perfect sequences of holds and pockets rewarding thoughtful and deliberate moves. At other times it can be delicate and near-treacherous with thin porcelain-like extrusions which you would never trust your full weight with, or steep and pumpy with arm-destroying sloper holds (The Nest/Wild Kingdom Wall, for example).
The other thing about climbing on Thai limestone is that you will get hot. Very hot. So it’s critical to chase the shade, avoiding direct sunlight like a chalked-up vampire. Sane climbers start on the west-facing walls and move to those facing east in the afternoon. Chalk can help, but with the more popular routes the sweat from a thousand fingers has mixed with chalk to create a slippery experience on some holds. Holds can also be very polished on the busier lines.
Ton Sai has definitely convinced me of the merits of limestone though, and of course it’s good to expand on climbing experience. It would be nice to go back to Interlaken one day, contact Davide, and see what else Hintisberg has to offer.