It is interesting nonsense.
There are a few interesting coincidences, but it is unfalsifiable. Sometimes a checkerboard floor os just a checkerboard floor.
Also, there is no real method behind the occult motifs the author selects. It is just a hodgepodge of whatever the author happens to know about the occult and wherever he can get a match.
Moreover, doesn’t it seem a bit strange that the writer finds nothing from Japanese esoterism?
But, it is amusing nonsense.