In any situation, it’s important to dress appropriately. It can be tough to get all the little details just right, though, especially when dealing with articles of clothing you don’t have occasion to use very often. If you’re still a student, for example, you might have trouble tying a nice, crisp knot in your necktie, and even if you’re an adult working in a suit-and-tie business environment, you might not know all the finer points for more formal accessorizing, such as where to position a tie bar or the proper way to fold a pocket square.

Or, if you’re going to meet up with your fellow samurai, should your sword point upwards or downwards?

If you’ve watched a lot of period dramas, you might have noticed that sometimes samurai wear their curved swords with the cutting edge facing the ground, and other times facing the sky. As it turns out, there’s a reason why, as explained in this illustration shared by Japanese Twitter user Suuko, who seems to be a pretty big fan of Touken Ranbu, the hit computer game that stars a cast of anime-style pretty boys representing actual historical samurai swords.

From the start of Japan’s Heian period through most of the Muromachi period (roughly the ninth to 15th centuries), a sword was a commonly and frequently used instrument of warfare. The samurai who carried them were often dressed in a full suit of armor, with the sword hanging from a cord attached to the waist.

As you may have guessed, that armor wasn’t made from papier-mâché. Anything that was going to protect a samurai on the battlefield needed to be crafted from sturdy, heavy metal. The plating along the upper arm and shoulder made it difficult for the wearer to raise his arm very high, but by keeping the cutting edge pointing down, the sword could be drawn simply by extending the arm forward.

Once Japan’s government was stabilized, though, open warfare became less common. With the end of centuries of civil war, most samurai in the 16th century and later were going about their business dressed not in armor, but in kimono, with their sword tucked into the sash holding the robe closed.

Having the sword’s edge facing the ground would put the sword’s hilt especially high, level with the ribcage. Unless the samurai had disproportionately long limbs, extending an arm upward to draw the sword would have been at best difficult, and at worst impossible, so instead swordsmen started wearing their weapons blade-up, making them easier to unsheathe.

Combine this knowledge with some period-appropriate toothpicks (and vocabulary), plus a propery tied kimono sash, and you’ll have all the fashion knowledge you need to be armed with confidence while being confidently armed.

Source: Twicolle, Twitter/Suuko