Oil-spot

This is,I think,a particularly spectacular version of the oil-spot glaze;we didn't see many examples on our Japanese jaunt-maybe only in this one gallery,that showed [among many other fine pots] oil-spot work from three potters:this piece was made by a potter with the unforgettable family name of Ii,and has a beautiful irridescence that suggests to me manganese in the mix .The oil-spot effect comes from red iron oxide in a feldspar glaze base letting go of one of its 3 oxygen atoms at around 1200 degrees.Given enough time from 1200 to 1300,the oxygen [carrying with it a scrap of iron] bubbles up to the surface of the glaze,and voila we have our oil-spot glaze.Like I said,I have been failing to get any results for 20-odd years.
I also got another video-clip together- thank you for your responses,please keep them coming- which I hope to launch on an unsuspecting world in a day or so.Meanwhile,for new readers,the first one should still be below.Please keep up the prayers and positive energy on our behalf.