Kento Guides
This registration method consists of a corner guide and a straight guide along one long side of the block. Traditional circles always carve the kento guides in a certain position on the block, I usually vary the positioning according to the particular needs of a print. For larger paper, I like to grasp the lower left corner with my left hand, so I carve the corner guide on the left lower corner. For smaller paper it doesn't really matter to me so I carve the registration marks where there is less image so that I will not have to wipe the marks every time I print.

The corner of the paper is placed exactly against the inside corner of the guide; then the paper is allowed to lay out, assuring that the long edge of the paper again meets exactly against the long straight registration guide.
Needless to say, the guides must be carved very precisely with a straight chisel coming down on the mark so that the inside edge leaves no room for placement error.
For a detailed explanation of the carving of kento guides, go to the Links page and from there to the Woodblock Encyclopedia. You will find registration notes in the Basic Process, One-point Lessons, and the Forum Archives.
 

Here the kento guides are carved right on the block, left bottom and middle bottom. This image did not need a large margin because the image itself is 23"x19". Also, I show the image sideways because that is how I printed it. It was easier on my back not to have to reach out 23" on the printing bench.	This is an adaptation when the block is smaller and a large margin is desired. "Wings" of plywood are glued edge to edge to the printing block. The kento guides, outlined in black, are carved on the added wood pieces.

Variations on the Japanese method
The basic corner/straight registration guides remain the same. The variations below allow for more flexibility on block size, border size, paper size, etc.
The other great advantage of the printing board, is that you can ink the block set apart from the registration guides. This way you can get clean margins without having to wipe down or mask the margins every time.

When a border is desired on a print with a small block, and adding wood on is not possible...

...the registration printing board comes in to the rescue! The moulding strips glued perpendicular to the edge of the board will be the paper stops. That is, the paper is placed against these moulding stops. The foam-board pieces are pasted down (wheat paste or something removable) to obtain a margin. The block is placed against the foam-board. Notice the opening on the corner, as shown in a picture following, this allows the thumb to grasp the paper at the corner.

Let's put the block and the paper on the printing board. Pause on each picture with your mouse to see the text.

Block in place against the foam board strips	Closer view of the block against the foam-board. Also notice the opening at the corner to allow the thumb to place the paper against the moulding stops.
Paper is being placed against the moulding stops	Paper is now against both sets of kento guides, corner and long edge Normally my thumb would be holding the paper in the gap at the corner the entire time (can't snap pictures that way)