The classic Leach 4321
From John Britt’s High-Fire Glazes book
Pete Pinnell’s Clear
Nigel Wood’s Porcelain Glaze
From Nigel Wood’s Chinese Glazes, page 263. Porcelain glaze, 1240-1290 degrees Celsius, oxidation or reduction.
This could also be classified as a Celadon, as the impurities in the kaolin and ball clay will lend it a bit of color. In my experience, changing the types of kaolin and ball clay used will significantly alter the appearance.