A reference for potters, from the first wedge to the last firing.

Techniques, clay bodies, a glaze library built from real tests, firing schedules, a troubleshooter for the day the kiln surprises you, and the long history behind all of it.

Open the glaze library Or start at the beginning

A Jian ware tea bowl with a hare's fur glaze, rust streaks running down a near-black surface — Tea bowl, Jian ware, Song dynasty. Cleveland Museum of Art, CC0

What's new

Everything new, by date

Tea bowl with hare's fur glaze, Art Institute of Chicago

6 Nov 2026 · Glaze test

Chasing hare's fur: one iron glaze, three cooling schedules

Same bucket, same cone 10 reduction, three different ways down. Only the slow one grew the streaks. Here is what changed and what we would try next.

3 Nov 2026 · Kiln opening

Sixty hours of stoking: a guest anagama opening, shelf by shelf

1 Nov 2026 · History

Shino: how Japan's first white glaze got its orange

29 Oct 2026 · Tools

Five cut-off wires, one clear winner

26 Oct 2026 · Materials

Added to the library: persimmon, russet and a cone 6 iron saturate

Reserved 728 × 90 on desktop, 320 × 100 on phones.

Where do you want to go?

Learn

Wedging, centering, throwing, trimming and hand-building, step by step with photos. The front door if you are new.

Materials

Clay bodies, and the glaze library: swatches, cones, surfaces and honest notes on how each one behaves.

A raku kiln with its chamber glowing orange

Fire

Kilns, cones and schedules, and the troubleshooter for crazing, pinholes, cracks, crawling and bloating.

Tools and studio

What to buy first, what can wait, and how to set up a corner of a garage so it works.

A potter at an anagama kiln, black and white photograph

Kiln openings

Photo essays from real openings, with the people who fired them, and what each load taught.

History and regions

Where pottery came from, the kinds there are, and how it is done differently today from Japan to Oaxaca to your town.

Glossary

bisque, bloating, cone, crawl, dunting, engobe, flux, greenware, leather hard, reduction, slip, wedging…

One short entry per term, linked from everywhere. About 300 of them.

Your own kiln log

Log pieces, glazes and firings as you go, and look back at what actually worked. Free, on your phone, at app.openthekiln.com.

Open the app

The glaze library

Every glaze with its swatch, its cone and surface, and the pots it has been seen on. Browse by color, then narrow by cone and finish.

Open the library

A pale green foliated plate with a lotus incised under the celadon glaze

Longquan celadonCone 10

A Jian ware tea bowl, near-black with fine russet streaks running down from the rim

Hare's-fur tenmokuCone 10

A thick white Shino tea bowl with an iron drawing of a bridge and shrine

ShinoCone 10

A large Shigaraki storage jar, orange clay with green ash glaze run down one shoulder

Natural ash, ShigarakiCone 10+

Iron redCone 6

A deep Jun ware bowl, opalescent blue with a purple splash

Jun blueCone 10

What went wrong?

Pick the symptom. Each page tells you what it is, what it is not, why it happened, and the one test to run next.

CrazingA web of fine cracks in the glaze, sometimes days later.PinholesTiny holes in the fired surface, like a needle went in.CrawlingGlaze pulled back into beads, bare clay between.DuntingA clean crack through the body, usually on cooling.BloatingBlisters under the surface, the body overfired.ShiveringGlaze flaking off edges and rims in sharp slivers.

Remember what you did last time.

The app is a kiln log that fits in your apron pocket. Record the clay, the glaze, the cone and the result for every piece, and the site's glaze pages will link straight to your own tests.