A piece of wood can be hollowed out with a carving blade or chisel. This technique gives you the freedom to create complex curved lines, surfaces, and round forms.
How to do kurimono woodwork
"What Are Traditional Crafts? -A Guidebook to Seeing, Learning, and Enjoying-" Edited by the Japan Kogei Association Eastern Branch. Published by Unsodo ／ List of works English translation: Kazuko Todate (Art critic / Art historian)