We arrived in Yangshuo and went for a cycle ride to pass the time before setting forth on our caving expedition. Erin and Duncan had commissioned these special trolleys with squeaky wheels that could fold and fit onto an overcrowded train within the exact parameters of the aisles. The journey took three days. The Chinese don't believe in barbaric ideas such as baggage allowances. The only real limitation is that it doesn't fall off on the journey.

En route to Wulong we hired a room in Luizhuou for several hours (it was that sort of joint), while waiting for our train. Duncan is proud of his chicken leg condiments. His T-shirt is from the 1999 Cambridge University Caving Club expedition to Austria. Becka's is from the 2003 expedition of the same. / The main bus stations all have these pointless X-ray scanners through which you have to push all your luggage. Notice that the man is watching us to make sure we perform this anti-terrorism ritual properly, right after we had spent several minutes in genuine fear of our lives crossing the normal traffic on a large road.

The bus to Houping, which is up in the mountains, has little wheels on the back end to prevent it grounding out too severely on the bumps. We bought blue string and strapped all our gear on top and hoped it wouldn't rain. Five hours later, we arrived in the metropolis of Houping where people eat rice in the street without fear of being run over because the road ends just beyond the next bend.

We left Houping for the two hour walk down through the excessively stepped landscape with perched paddy fields and potato plants by the billion. Every bit of it is handmade and handplanted by Chinese peasants. It's frightening to think how much work they will achieve once they get their hands on some serious machinery.

The little hamlet of Er Wang Dong, named after the cave Er Wang Dong ("Second Great Cave", pronounced Ar Wong Dong). We stayed in the middle dwelling in the building at the front, Mr Wang's house. Mr Wang was busy ploughing his fields during the day. I am told he is the chief of the valley, but he seems to do a lot of labour and no paperwork for someone in such a position. Don't be fooled by the satellite dishes. I don't know what they were doing there, but they appear little more than scrap metal.

Here's the corner of the living room. Some pig fat hangs above it. Maybe it's getting smoked along with the rest of the house. Maybe it's going green with mould. We ate it all the same because that's what Mr Wang cooked for us. The other picture is the fitted kitchen with installed woks above mini wood fires. Most of the time the near one was used. The far one was a usually boiling pigswill.

This is Erin coming up the stairs to see Duncan in bed in a room full of potatoes that are sprouting everywhere. The place got swept up the next morning. The women slept in the spare bed in Mr Wang's room which is smaller and more comfortable, except he snored. It's three-star accommodation: you can see two of them through holes in the roof. There is no glass in the window.

Chimneys, now they're a good invention if you are intending to cook over a wood fire indoors. One reason for omitting such a device, apart from on grounds of cost, is so that the smoke filters out through the roof and discourages mould and vermin, such as rats, insects, birds, and male cavers from roosting there. The picture on the right is of Mr Wang's son making tofu by grinding soy beans in a really clever stone mill. I'm not sure how all of it works, but the stick he is holding is pushed forwards and back to make the huge stone cylinder with the hole full of soy beans rotate like a crank.

The best feature of the whole establishment is the privy out front which embodies ten thousand years of agricultural development under one small roof. On the way in you pass the hen basket. The crack between the floor-boards ahead the totality of the toilet which you use squat style. It's so much easier than having to worry about whether the seat is clean.

Right next to you behind the right hand wall are the pigs. They make a lot of noise and want to eat your toilet paper. On the other side are the tractors. (Chinese are not into milk.) Six inches below the floorboards is the black pit of sludge crawling with maggots (not photographed in focus) that stir everything up within minutes before it has a chance to smell.

Here's the balcony out front. I think the corn is for the chickens, but they don't seem to get fed it very much. There were several incredibly muddy preschool children whose job it was to get their fingers into everything. The house next door had dirt floors rather than concrete for that extra sense of dustiness.

We did a bit of caving, which my camera was not up to the job of photographing. The Chinese had done a lot of caving before us and built these pits all over the place, supposedly for separating out nitrate from the soil or guano (bat shit). I am very unclear about the process and haven't seen an authoritive explanation yet.

A view of two tiankengs (or dolines). These are enormouse speleological craters with no obvious means of formation. The picture on the left from a newly discovered ledge in the ceiling of the huge tiankeng in Er Wang Dong. It's not a good ledge because it's comes out in the ceiling of a larger tunnel at base level and ends with a sandy slope over 40m above the floor. You don't know how solid the rock is beneath you. The picture on the right is from the smaller but much more picturesque tiankeng in San Wang Dong, where there was enough light for moss and flowers, and you can see other parts of the cave system being intersected by this vertical shaft.

This is a view back from the ledge in the San Wang Dong tiankeng. We found about eight windows into it on this level, all equally lovely. I can't wait to see surveys of this area in coming years where this place could act as an axis of entry into the many different levels of the system. On the right is part of the obscure passage connecting the main cave area which we (re)discovered to the tiankeng. The chinese nitrate miners, we are sure, came in through some route in the tiankeng (which we could not find) and hammered their way through any of the calcite blockages in the passages they wanted to get down through. It must have been a lot of work. Nowadays, cavers use capping technology, or explosives, to get past inconvient rocks.

This is dinnertime in the Wang household. You can eat anything after a caving trip. Even crap beer tastes lovely. You feel good to be alive and out in the open, even though you are filthy. Chickens, however, don't usually go caving, and tend to spend all day clucking and squawking and wandering around. Mr Wang got annoyed with their noise one morning and collected his six in a bunch, tied their feet together, and threw them under a basket in the mud. We honestly thought we were going to get chicken for dinner, but it turned out to be the usual rice, sugared pig fat, and potatoes if we were lucky. On the third day there was a storm and the water streamed under the basket all night. We were surprised that only one of the chickens was dead when he let them out looking much worse for wear. They seemed to recover their plumage after a week, but remained much quieter from then on. And so did we.

On the last day of the expedition we hired some help to get our stuff up the hill. The locals have these stiff basket backpacks with shoulder straps that are as padded as cheese wire. We hired as many as we could get so they no one had to carry too much. Mr Wang looks pretty pleased to see the back of us, don't you think? Erin stopped off on the drive back down from Houping to look for more cave entrances. She's acting as a sort of caving estate agent for other clubs, to find them areas where they can establish exciting new expeditions. Us blokes avoided this chore and tried to get a head start with the eating and drinking down in Wulong. But the bus broke down on the way. We sat on the side of the road racing caterpillars until some genius showed up on a moped and fixed it. I don't know how. The gearbox had sounded like it was gone for good.

The neverending journey back after the caving expedition involves eating and drinking as much as you can to make up for lost luxuries. The bubbling couldran of red liquid is chilli oil, water, and seshwan peppers (not hot so much as flesh numbing) is called a Qongqing hotpot. The little bowls are full of sesame oil, not rice, which you use to wash off the worst of chilli oil. I think it acts as an effective antidote to the sting, in the way that milk and yoghurt do not. The train ride was only 36 hours long and we got through every bottle of wine.