Top is the hidari-ba, the bottom is a cutting knife.
Among the video series for beginners, the first featured hand saws, the second files, and now carving tools known as hidari-ba (lit. left-blade) knives/scrapers.
The hidari-ba and the method of use were invented in the later Edo period (17th to mid 19th century) to carve ivory and similar materials, and have allowed ivory carving more efficient and exquisite. They can also be used in carving wood. (I will give more details in the future.)
In this video, my father explained the differences between an ordinary cutting knife and the hidari-ba. In essence, the oridnary knife has its blade (or the tapered side) on the right, while the hidari-ba has the blade on the left.
In passing, the hidari-ba shown in the video is for right-handers. For left-handers, the blade needs to be made on the right.