Some background on the video: the hand you're watching belongs to 荆霄鹏 (Jing Xiaopeng, b. 1976), one of China's best-selling copybook authors — 400+ published practice books, and calligraphy teacher at Tsinghua's Academy of Arts & Design.
He's writing 硬笔楷书 — "hard-pen regular script." Same discipline as brush calligraphy, but done with an ordinary gel or fountain pen, the way schoolchildren across China still learn to write today.
The style has a 1,400-year pedigree. Jing is a direct disciple (入室弟子) of 田英章 (Tian Yingzhang), the most famous living master of the "Ou school" (欧体). That school traces back to 欧阳询 (Ouyang Xun, 557–641 CE), calligraphy authority at the early Tang court and one of the Four Great Masters of regular script. His inscription 《九成宫醴泉铭》, carved in 632 CE when he was 75, has been THE model text for students of this style ever since.
Ou style is famous for 险劲 — "perilous rigor": tall, razor-precise structures that look daring but lock together perfectly. Tian Yingzhang inherited that strictness; his student Jing softens it slightly — reviewers call his hand 秀气, graceful.
So the lineage in this clip: Ouyang Xun (Tang dynasty) → Tian Yingzhang → Jing Xiaopeng → the numbers 一 through 十, written with a ballpoint pen.
I'm cutting these follow-along reels (½ speed, then normal, then a freeze on the finished character) for each lesson of the DeFrancis Chinese reader as I learn to write.