This is a responsive adaptation of Zenstat's original tool.
Words from Zenstat, creator of the tool:
This is an interactive diagnostic key which should help you identify the trademark stamp on a K Zildjian Istanbul cymbal. The identification information and years are based on the pioneering work of Bill Hartrick. I'm responsible for any mistakes in my interpretation of his stamp identifying features. Bill has sole responsibility for the years as I haven't examined those at all. His work is published in pages 250-251 of Rob Cook, The Gretch Drum Book, Rebeats Publications, 2013. I recommend you rush out and buy a copy if you are serious about identifying your K Zildjian Istanbul cymbals. Especially if you are also keen on Gretsch drums. There is more detail in there than I've implemented so far.