So, first you need to decide on what coins you'll use for Go stones. I chose UK 1p and 5p coins as they're pretty small. The 1p coin is the bigger of the two so the squares on the board need to be just a bit bigger than the diameter of the 1p coin.

I also decided at this point that I'd make the board double sided. One side would have a full 19x19 board on it, and the other side would have a beginners 9x9 board.

On the 19x19 side I made each square 2cm x 2cm. This made the playing area 36cm x 36cm. Remember: in Go you play on the intersections, not in the square. On the 9x9 side I made the squares 3cm x 3cm (to use up a bit more space) which makes the play area 24cm x 24cm.

The board that I cut needs to be a few centimeters larger on all sides, so I cut a board 46cm x 46cm.

I won't bore you with the 'here's me cutting a piece of wood' stuff.

With the board cut, and sanded a bit, I marked the centre of the board (with a pencil, and marked lightly) and worked from there out to make the outer edge of the play area, then marked each edge on the 2cm/3cm mark.