[jere]

They addressed this in an update:

>In general, if you drill down deep enough on the actual sword techniques, the tree of possible outcomes gets pruned way down. It turns out that you rarely have to solve the fully general problem of one sword stopping another sword traveling at top speed at an arbitrary location in space. Which is a hard problem!

There's a longer explanation here: http://www.kickstarter.com/projects/260688528/clang/posts/24...