I noticed that when the boards are overlaid like so, the corner hoshi are also the tengen hoshi for the next larger size. By this series, the next board size will be 31x31, with tengen at the 16-16 point.
31x31 also fulfills the formula that yields six lines between hoshi along a side, as proposed elsewhere [citation needed: see Oct 2021 of EGJ].
A board of size 31x31, assuming regular sized stones, makes for a physical board approaching the limit that a player could reach across while remaining seated. It’s a stretch, and some people may have to stand. You could reduce the physical dimensions by using smaller than normal stones.
Another very large physical board that has been made (and played) is 43x43, but at that size you will have to walk around the board to make your play.
I made a 31x31. It’s 28 ⅛ x 29 ⅝ inches of plywood. stain. inked lines. polyurethane sealer.
Now I need more stones to play it!
Serious question: how many stones do you think I should have to make it a set? It’s 961 intersections, but 481 black and 480 white stones is probably quite a bit more than practically needed.
That’s a nice looking board. I mean maybe two sets of stones and ~360 ish could be enough and swap prisoners if using Japanese rules, but it’s hard to know
I’m kind of imagining some 19x19 games being like 200-250 moves or say 100/180 or 125/180 stones potentially used, vs say 360/480 on the board. If the game is one sided I suppose one player could end up using a lot more stones than the other.
It could also be a cool board for multiplayer go with multiple coloured sets, just given the size of it
