I knew about the two battles with the Mongols, but nothing about the replacement sword. Immediately, I started looking for a current release of the sword. Was looking for an item shorter than my katana or wakazashis. I have two handed knife with an over all curvature running through the blade that I commissioned about 30 years ago from Barry Dawson. Still wanted a shorter knife and knew I would have to settle for one handed handle and not enough curvature. So, I had a Cold Steel Recon tanto come in today.
That's why they were invented. They made it possible to compete in combat without a lifetime of training.
The exception is learning the basic concept of movement called "shooting" in san soo which is a movement past the aggressor without striking or being struck while protecting your head. The movement is completely unexpected by an aggressor. No grappling.