The kimono (着物?, きもの) is a Japanese traditional garment. Kimonos were very common and would have been worn by shinobi no mono.
The Shoninki shinobi manual mentions the kimono on several occasions. In one instance it is mentioned that it could be used when mimicking a dog at night. Dogs sometimes tremble when they growl, which could be mimicked by shaking the edge of one's kimono. In another instance, it is mentioned that charms are kept in the folds of a shinobi's kimono in order to have better encounters with a target or create discord between the enemy and his retainers.