Ron,
indeed a very fine example of a twistcore! Iron must be of very good quality to allow such fine texture without any blowholes, caused by impurities and air pockets. The torsion of both bars has to have almost the same frequency to become the pattern almost symmetrical as it is in this case, the welding in areas depicted is very near to perfect.
Becouse of the theme of this thread I thought more of examples, where the central twistcore panel is etched. I have found three examples in the Forum, yet there should be more perhaps:
http://www.vikingsword.com/vb/showthread.php?t=798
http://www.vikingsword.com/vb/showthread.php?t=1267
yet especially this one:
http://www.vikingsword.com/vb/showthread.php?t=8641, #19 and 28. Even more impressive in pictures from Ashoka arts.
Actually you (almost) always see the difference between real Pamor and an etched one at the base of blade, and even more in area, where the twisted bar ends. To control a Pamor near the tip of the blade is the most difficult part.
Kind regards,
Gustav