Used my favorite antique cutthroat, the Johan Engstrom frame back.
I'm continually impressed with the quality of Stirling's soap. Today it produced a cloud of silky cream that looked so good you could eat it. Great slickness on the hide, and the result was a beautiful shave - two passes and a bit of touchup, minimal blood, near perfect shave.
That Engstrom is so sharp that when I accidentally lightly touched it with my pinkie during the shave, it cut the darn finger. What an edge!