There is a consensus that Stone 56 (the tallest one) was re-erected by Gowland in 1901 in the wrong place. Alexander Thom stated it was 60cm out of its original position which Mike Parker Pearson in his recent book dismissed and claimed it is just 30cm out.
As far as I can tell this belief is because the stone is twisted and not symmetrical within the inner horseshoe. Most writers, and many plans, assume this symmetry was meant to be and dismiss the imperfection as a mistake.
I don't think it is a mistake, I think it is deliberate and has meaning. But before I develop that idea further I need to show why I think Gowland re-erected the stone in its original position.
Gowland wasn't just a skilled engineer he had also excavated hundreds of Japanese archaeological sites; he was familiar with archaeological digging.
Reading his report it is obvious he was methodical and careful, and he included detailed plans of his excavations.
I have collected relevant sections of his plans in this diagram.
(Please click on the diagram to expand it)
The method used to raise stone 56 from its precarious leaning position was to dig behind it in three sections. Each section was cleared individually and concrete used to reform the back stop before the next section was started. As can be seen the original back wall of the hole could be clearly seen and with the adjacent section undug it was easy to create a new concrete back wall in the correct place.
The front section was not dug until the stone had been raised so preventing it moving forward. The stone pivoted on its base and as can be seen and measured in the plans accompanying this post, it returned to being against the original position of the back wall of its hole. Because of the pointed nature of the bottom of the stone it was necessary for the stone to be corrected from the side with hydraulic jacks once upright, showing again the care he took to replace it in its original position.
There may be a centimetre or two difference in position arising from imprecision of excavation but unless evidence can be produced that contradicts the excavation report it is incorrect to say that Stone 56 is not in its original position.