Summarize this article:

You can find one in the woods or you can buy something which is similar, like a 2" diameter dowel rod. You can buy dowel rods at your local hardware store for just a few dollars.    {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/d\/d8\/Make-a-Ninja-Sword-Step-1Bullet1-Version-2.jpg\/v4-459px-Make-a-Ninja-Sword-Step-1Bullet1-Version-2.jpg","bigUrl":"\/images\/thumb\/d\/d8\/Make-a-Ninja-Sword-Step-1Bullet1-Version-2.jpg\/aid461482-v4-728px-Make-a-Ninja-Sword-Step-1Bullet1-Version-2.jpg","smallWidth":460,"smallHeight":334,"bigWidth":"728","bigHeight":"529","licensing":"<div class=\"mw-parser-output\"><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"} Real ninja swords were short, allowing them to fight it close combat and move more easily. A good rule of thumb is for the blade to be the same length as the distance from your elbow to the tips of your fingers. Just be sure to leave an extra 4-8" for the handle on the end. Shave off the bark using a knife or whittling tools. If you are using a dowel rod, this will not be needed. Using a knife or whittling tools, carve the sword blade into the shape you want. Point the tip and add some curve if you want to, but real ninja swords probably had little curve and an angled point. Once you've got the rough shape that you want, use sandpaper to get the final look right. Sandpaper will make it easier to get the shape just perfect, since it only removes a little at a time. Using some electrical tape, wrap the handle of your sword. Cut a piece of cardboard so that it will fit down over the blade. Paint it black and slip it on to create the hand guard. Do this from the blade side, not the handle. Use some extra tape to really seal the hand guard to the main part of the sword. You can make your sword look even cooler if you want to, by painting the blade silver. Use tape and newspaper to protect your handle and then use silver metallic spray paint to paint the blade. Do this outside. When it's done drying, enjoy your new sword!

Summary:
Get a thick, straight stick. Cut the sword to length. Clean up the wood. Carve the sword into the desired shape. Sand the blade smooth. Wrap the handle. Create the hand guard. Slide the hard guard onto the sword. Tape the hand guard in place. Add finishing touches.