Tachi versus katana in horseback fighting

[tsubame1]

Originally Posted by Chris Evans

2. tsubame1. Thanks for posting those pictures. Do you know when they were painted? The one on the left looks 19th century... I have a painting, I believe from the Kamakura era, that depicts a samurai afoot, with a two handed grip on his tachi, so they were essentially a two handed sword as I said at the outset, though they could be used with one hand. However, as a Japanese expert explained to me, who was very conversant with Euro sabres, it is very difficult to effectively wield a Japanese sword with one hand (the hilt!) and this is why Musashi's advice was not taken up all that enthusiastically.

I'm not specialized in painting, I'm specialized in weaponry. If you have transmitted your suggestions to your japanese friend, being the Tachi used with two hands from horseback, you should have been already advised of your error by him.
More, even if the pictures are affectively (not late) Edo products, I would suggest that being the Edo the period of Katana, if the artist was in error in his depiction, as you tacitly suggest in your statement, he would have been portraied the horseman with a two-handle grip rather then the single-hand one. This is, IMHO, a further evidence that they were and are well aware
on how a Tachi was used *by horse*.

And now, to stop this mirror-climb you're making, you force me to remember that the responsibility of proving your assertion is yours.
As seems you'r familiar with Kamakura-era paintings, likely worthing thousand of dollars, please post a Kamakura Era picture depicting a Samurai cutting
with a Tachi using a both-hands grip from horseback.