As hobbies go, you might describe mine as, well, quite bloodthirsty.

While some prefer to play tennis, my bent is to annihilate at least 43 people on a weekly basis. My accomplice in this hideous crime is a mid-17th century, razor-sharp shinken (real sword). But before you call the police, please give me a few minutes to explain myself.

The fearsome opponents I chop down are merely figments of my imagination, which is what you do when you practice the martial art of iaido, as I have done for the last 13 years. Often described as the art of drawing out and cutting with a Japanese sword, iaido has many styles — but all are said to derive from one created by Hayashizaki Jinsuke Minamoto no Shigenobu, a samurai who lived around the beginning of the 17th century.

Originally developed as a way to deal with an unexpected attack, iaido’s prime feature is that its practitioner’s weapon is drawn in a variety of ways — known as waza — each of which is appropriate to a different threat. The style of iaido I practice is Muso Jikiden Eishin-ryu, which comprises more than 60 waza that start off from a sitting or standing position.

To get an idea of what a waza is like, let’s have a look at one called kazumi, which means “mist.” At first, both you and your imaginary opponent are sitting in the tatehiza position, with our right knees up off the ground — supposedly on the premise that we are both wearing armor. Then, you sense that your opponent intends to kill you, so you move a fraction before he does, and manage to slash him horizontally across his body, just below the shoulder line. The force of the cut is enough to push him back, so you then move forward to pursue him and cut him just below the kneecap. The coup de gra^ce is a downward cut from his head through the body center. The waza is over after you resheathe your sword.

All this may sound macho, but in my humble opinion iaido is more than that. Done alone, it forces you to focus inwardly and work on yourself, rather than trying to humble others. In fact, iaido has often been described as “moving Zen,” which is apt considering that its practitioners strive for a perfection that can never be achieved.

That, though, won’t deter me from going to practice next week, putting my sword in my belt, taking a deep breath and facing whatever opponent decides to cross my path. All I know is that I will be the last man standing.