I must agree with the fellow reviewer who found this version of Daibosatsu Toge (The Great Buddha Pass) not as interesting as the Ichikawa Raizo version from a few years later.
Sword in the Moonlight is a decent samurai film, but since I have watched Sword of Doom and all three Satan's Sword movies, I felt somewhat underwhelmed by this version. Of course, I am aware that the Sword in the Moonlight films came before Satan's Sword, but it comes after the Ichikawa Raizo in my film viewing life. There are differences. For instance, in Sword in the Moonlight, the villainous Ryunosuke Tsukue does not sleep with his rival's wife until after the duel. I was also glad that this first film did not end on a cliffhanger like the first two Satan Sword films. Sword in the Moonlight has aspects to recommend it.
In the end, I think the problem rests with the leading actor. Chiezo Kataoka is a decent actor, but he is no Ichikawa Raizo. Furthermore, he was in his mid-fifties when he made Sword in the Moonlight, which seems a bit old for Ryunosuke Tsukue, at least for me (others may not have that problem).
I have not read the source material, so perhaps Sword in the Moonlight might be closer to the spirit of the books. I do know that, as cinema, I preferred Satan's Sword from 1960.