The crowbar effect, that is why you will notice the Germans don't have their braces pushing against the posts, or if they are against the posts they are directly opposed with another brace on that same post. These posts typically extend all the way from sill to plate, or they may start at the sill just inside the corner post and brace against the next post, with another brace directly opposite in the next cavity there to ensure the post doesn't go anywhere.
Use wall ties too, 1 or 2 horizontal timbers that span the cavities between posts. This will have the effect of causing the posts to press against each other. If one post wants to flex, it would have to flex all of the others with it. These don't have to be very big at all, they aren't bearing any roof loads or other structural loads. They just need to be stiff enough to be able to push. They would work with the same dimensions as brace stock.
