"Tang Zhang Huaiguan's Treatise on Ten Techniques for Using the Pen" on paper, 46.7 cm in height and 37.7 cm in width, collected by the Beijing Cultural Relics Bureau

This work uses regular script, running script, Zhang Cao and other calligraphy styles, and is recorded in Zhang Huaiguan's "On Ten Methods of Using the Pen" of the Tang Dynasty. The style of the calligraphy changes freely, the pen is used freely, the roundness and vigor are flying, and the charm is simple and lush.

Zhang Huaiguan of the Tang Dynasty discusses ten methods of using pens
Yan Yang to the back: It means that the two characters are combined into one character, and it is necessary to draw the upward and downward posture of Yan Yang and Lihehe. The yin and yang correspond to each other: it is said that yin is internal and yang is external, concentrating the heart is yin, and spreading the pen is yang. The left and right sides must correspond. The scales and feathers are uneven: it means that the stipples are not arranged evenly, as if the scales and feathers are uneven. Ups and downs of peaks and ridges: It means that the starting pen is frowning, just like the shape of peaks and ridges, and the killing pen must also be knotted. True grass is withered: It means that two characters make three characters. Real grass cannot be combined into one character. It is said that it is withered. It needs to be reflected and the characters are majestic. The principle of evil and true loss: it is said that the method of writing and finishing words must be in accordance with the order. Sluggish and flying: It is called Le Feng Zeng's pen. The characters must be flying and there is no stagnation. This is the method. Shooting in the sky is exquisite: it means that you can read with the sense of smoke, use a pen to write cursive, and don't follow the front and back. Dimensional rules: It means that the length should not be too long and the shortness should not be enough. The pen must be drawn to the end, so that the characters will have a dignified look. Change with the character: For example, in "Lanting", the character "Sui" is written in one stroke, forming a hanging dew; the character "年" above it becomes a hanging needle; and there are eighteen characters for "Zhi" in between, each with its own style.