The Jianshui teaware culture has grown alongside the development of Pu-erh tea culture in Yunnan. Twenty years ago, this small city in Yunnan was famous for vases, plates and other kitchenware. As tea enthusiasts were flocking to Yunnan in search of good leaves, the ceramicists of Jianshui took up this opportunity, refined their technique, trained their kids. Artists from other regions settled down and shared their techniques. Jianshui is now a reputable source of teaware for the Gongfu brewer.
Most of the teaware in Jianshui is made of a mix of five clays, fired in a reductive environment (with a lack of oxygen in the burning chamber) which gives Jianshui teaware its typical dark color. The chinese calligraphy or illustrations you can see on the teapots are not painted,if you run you finger on them, you'll feel they are not completely flat. It's actually colored clay. The teapot is carved when at the leather state (half dried, not fired yet) and then filled with colored clay before being cooked.
Jianshui teaware feels particularly heavy in the hands of the tea brewer, this is because the clay has a fairly high density, and also because it cracks easily during the firing, it can't be trimmed as much as Yixing teaware, the shapes have to be kept quite thick if you're using the traditional blend of five clays.
Of course, due to Jianshui being the most famous place for ceramicists in Yunnan, a wide variety of techniques and styles will be found nowadays: non-reductive cooking (the clay remains red) and wood-firing (with a lot of random patterns and a more rugged feel) are quite common.
Jianshui pots are typically not made by a single artist. Although the workshops are small, they tend to have specialists. The clay blend is made by one business, then the potter will shape the pieces, then a professional carver will do the drawings and someone else will take care of the firing.
The traditional blend of clay will have a small influence on the taste of tea: it will make it feel more mellow than porcelain, but not to the extent of Yixing purple clay, you can still do a fair tasting with Jianshui clay. The seasoning of the teapot will occur over the years, but more slowly than in Yixing pots.
They make good daily tools for tea brewing because they are really designed for tea drinkers. Jianshui has put the emphasis on usability over aesthetics from the early days of teaware making. The pots are sturdy and won't be chipped as easily as porcelain.