Unless you are Conan or Xena, the sword is worn horizontally through the obi. The obi itself should be as long and as wide as possible and is worn under the hakama. The scabbard slides in front of your belly button comes out of the left hakama "pocket".From Jitsuka
* The sword is generally horizontal.
* The cutting edge is uppermost.
* The guard is in front of your belly button.
The obi should be tight enough to take the weight but loose enough to allow movement. To stop the katana sliding out when you move, grip the top of the scabbard with your left hand and put your thumb onto the guard about 45° from vertical.
The most striking difference between tachi and katana is that the former is worn suspended from the waist, edge down, while the latter is thrust through the sash and worn edge up. When we speak of tachi-mounts or katana-mounts, we are referring to swords with furniture specifically designed to suit one or the other way of wearing.From Japanese Garb
During the year 1337 to 1570 (Muromachi period), long and heavy swards fit for one on one fights were in demand by many samurai warriors. Those swords produced from the 14th century to Sengoku period were heavy and some were longer than 3 ft. (90cm). At the end of Sengoku period, many tachis were cut shorter, and the concept of "tachi wearing" (TACHI KOSHIRAE) changed into "katana wearing"(KATANA KOSHIRAE). This caused the loss of many good swards with production dates and signatures.From Samurai Swords
Those swords made during MOMOYAMA period to KEICHO-NENKAN, 1596 to 1614, are known as KOTOU or FURUI KATANA. Katanas produced after this period are called SHIN-KATANA.
During 1868 to 1926 (in the beginning of SHOWA era), SHIN-SHINTOUs were made, and SHOWA-KATANs with machine-made blade followed.
SAMURAI --- A class of people that existed in old Japan. Consisted of about 2 million or 3% of total population.
TACHI KOSHIRAE --- Wearing method of swords. The sword is hung from a belt with the cutting edge facing down.
KATANA KOSHIRAE --- Wearing method of swords. The sword is hung from a belt with the cutting edge facing up.
So in sum: katana are worn edge up. L5r's claim that they are worn edge down is wrong. Not critically but it is an error. Tachi, the slung swords that went out of fashion as cavalry became less critical, were worn edge down because they were worn differently (i.e. slung rather than thrust through an obi).
If Becca and Reed get to flip out about costuming I get to flip out about swords being flipped. Nothing needs to be said but I wanted it clear I was not talking out of my ass.
If you're still reading this I appreciate your patience. Have an iaido video as a reward.
Technically battojutsu but shows draws from several blade attitudes
Bunches of stuff (the katori shinto ryu iaijutsu is the style that I'm starting to learn)