On Dan Penrod's article
here, first picture to the right is of Ueshiba knitting... finger knitting that is...
The image caption reads: "Masumi Matsumura and Morihei Ueshiba performing chinkon kishin in Mongolia, 1924".
Elsewhere, I've seen photos of Ueshiba standing and doing similar finger knitting. Whether there is a link between kuji-in and Ueshiba's purported mystic powers ... I'll leave people to make up their own minds.
Suffice to say, the Tantric practice, as it pertains to Japanese martial traditions and qigong generally, is cursorily documented in a few (slightly more authentic) places... for example,
here,
here and
here.
As for the website... no comments.