A clear parabola traced by chalk on the blackboard ends with the bell, as it lands neatly back in the box. The classroom of Class 5, Grade 3 at Jinta County Fourth Middle School in Jiuquan bursts into lively chatter. A few students gather around the podium, asking, "Teacher Fan, are we filming this afternoon?" Standing among them, Fan Yulong smiles and replies, "Yes!"

Born in 1996, Fan is both a serious educator in class and a playful "leader of kids" after school, as well as a warm-hearted online influencer known as "Brother Guji." His story began in 2018 when, as a fresh graduate, he faced a crossroads: stay in the bustling city or venture into remote mountainous regions. "I wanted to challenge myself!" Fan declared, packing his bags for Shijiagou Primary School in Dongxiang Autonomous County, Linxia Prefecture.

Between lessons, he documented his teaching life on social media. Starting with just 35 followers, his breakthrough came when he filmed students walking alone on mountain paths after school. The video went viral overnight, gaining over 70,000 followers and an outpouring of support—donations for books, winter clothes, and even a new playground.

After his one-year stint, Fan returned to his hometown, Jinta, where many children were left behind by migrant parents. He taught first at Dongba Town Primary School and later at Jinta County Fourth Middle School. Over five years, his online presence grew to 6.5 million followers, with videos amassing over a billion views. "Some call me an internet celebrity, but I know the real value lies in drawing attention to rural education," Fan reflects.

Now, his mission extends beyond the classroom. On weekends and holidays, he promotes local honeydew melons and goji berries as "Gansu's Most Beautiful Hometown Ambassador." He launched the "Spark Project," training 30 students as campus digital ambassadors. Inspired by him, former students have even started university charity clubs.

"Education is about passing on the flame of civilization. If there's a chance, I'll teach in remote areas again," Fan says firmly. His phone still holds a message from a Linxia student: "Teacher, we’ll study hard, leave these mountains, and see the wider world."