Yubetsu technique

The is a special technique to make microblades, proposed by Japanese scholar Yoshizaki in 1961, based on his finds in some Upper Palaeolithic sites in Hokkaido, Japan, which date from c. 13,000 bp.
The name comes from the , on the right bank of which the Palaeolithic sites were discovered. 
To make microblades by this technique, a large biface is made into a core which looks like a tall carinated scraper. Then one lateral edge of the bifacial core is removed, producing at first a triangular spall. After, more edge removals will produce ski spalls of parallel surfaces. 
This technique was also used from Mongolia to Kamchatka Peninsula during the later Pleistocene.