Unlike Renboshiki-noborigama, the flue gases (flame) in Anagama go straight through the kiln and since there are no convection currents, the position of ware relative to the fire and the amount of ash coating produce patterns and colors that even craftsmen cannot anticipate, resulting in tasteful pieces of which it is said no two are the same.
とりわけ穴窯は燃焼ガス（炎）が窯内を直進し、連房式登窯とは違い、窯内で対流が無い為、火のあたり加減と灰のかかり具合によって作者も予期しない模様や色に焼きあがるため、味があり、同じものは決して二つとしてできないといわれている。