This picture is of a repair made to one of the large columns supporting the gate to the Osaka Castle in Osaka Japan. I am not sure of the size, but it is in excess of 2 feet square. The base of the column was replaced at some point with new wood using the interesting connection shown. The same dovetail shape appears on the backside of the column.
The solution can be seen in the sketch in the following post. Try to figure it out before you look at the next post.
Stan