They didn't mention bo-shuriken[1], which is a spear-shaped throwable metal "dart". The throwing technique is in some ways similar to the way a katana is swung. A circular motion, taking the hand behind the wielders shoulder and unrolling straight in the opponents direction. As there is no rotating motion involved, these are short range projectiles. The ones I saw were top-heavy and had tail feathers. Checking the YouTube videos, some users instruct a more knife throwing grip. However, the technique explained to me was leading with the back hand side, releasing the dart from the palm[2] towards the end of the motion.
[1]: https://www.google.com/search?q=bo-shuriken&safe=off&hl=en&b...