Oil pastel

[1] He thought that it had been geared too much towards uncritical absorption of information by imitation and wanted to promote a less restraining system, a vision he expounded in his book Theory of self-expression which described the Jiyu-ga method, "learning without a teacher".

Teachers Rinzo Satake and his brother-in-law Shuku Sasaki read Yamamoto's work and became fanatical supporters.

For this, they decided to produce an improved wax crayon and in 1921 founded the Sakura Cray-Pas Company and began production.

[1] The new product was not completely satisfactory, as pigment concentration was low and blending was impossible, so in 1924 they decided to develop a high viscosity crayon: the oil pastel.

[1] State schools could not afford the medium and, suspicious of the very idea of "self-expression" in general, favoured the colored pencil, a cheaper German invention then widely promoted in Europe as a means to instill work discipline in young children.

[2] These were superior in wax viscosity, texture and pigment quality and capable of producing more consistent and attractive work.

[1] The Japanese Holbein brand of oil pastels appeared in the mid-1980s with both student and professional grades; the latter with a range of 225 colors.

The medium has known durability problems: A work is easily made transparent again by gentle polishing with a woolen cloth, but the three issues result in a color layer made up mainly of brittle stearic acid on top of brittle paper, a fragile combination that can easily crumble away.

It is generally meant for children or new users of oil pastels, and is fairly inexpensive compared to other grades.