Actually, they are, just hakama with drawstring in the ankles. It blouses out the legs and reduces the appearance of the pleats. The slits you see at the sides and the way it's tied in front are a clue. Here's a link to information on the various clothes in Inuyasha's outfit: http://en.wikipedia.org/wiki/Inuyash... al_context.22
It's possible that Inuyasha's hakama are made with fewer pleats in front than you see on standard hakama: the average number is around six in the front (3 to each leg) and about 2 for each leg in the back. The pleats in the front are laid side by side in regular hakama, like the pleats in Kagome's skirt, while they're laid on top of each other (sandwiched) in the back. If you're going for authenticity, I wouldn't iron the pleats like they tell you to for hakama; just make the fold/folds at the waist, sew across to hold them in place, and finish.
You can just use a bellydancer-style pattern if you're only concerned about getting the fullness, but if you'd like to go authentic, here's a link to the pattern-making instructions I'm using in my hakama. It's a bit time-consuming, but not too difficult so far. You'd have to alter it a bit. The section used for the front of the leg is wider than that used for the back, to accomodate the extra pleats. You'd probably want the width to be the same for the front section and the back. And you'd have to add a drawstring or elastic in the ankles.
I believe this is the pattern they recommend for Bleach cosplayers. In any event, it would give you the proper sides, belts, and back board.
Why yes, it is my natural hair color, darling!
Working on: Sakura/Syaoran/Tomoyo fall uniforms, Ashitaka
Ashitaka (Princess Mononoke); Sakura Kinomoto (Cardcaptor Sakura)
Autumn '08/Aki Con
Ryoga Hibiki (Ranma 1/2); Shura!Sakura, Jade!Syaoran (Tsubasa: RC); Kokon (Kon Kon Kokon)