This is a rare and unique Zildjian prototype. The serial number date code is AE - 2015. It has the artificial patina finish found in the Kerope line. Hammering is also consistent with the Kerope cymbals, though it does not have the over-hammered bell. Shows stick marks and fingerprints from normal use. This is a great sounding cymbal. Cymbal weighs 2302g. Definitely unique.
While I do not have confirmation, I believe this to be one of the 50's K Istanbul inspired rides demonstrated at PASIC 2015. Paul Francis described these cymbals as being modeled after an old K owned by Billy Drummond. Use the google search "Vintage K Prototype PASIC 2015" to find the video with Paul Francis describing the cymbal. Again, I cannot confirm this is the cymbal he described, but it looks very similar and the date code fits.
