What calligraphy technique is used in the plaque of Yuelu Academy?

The existing "Yuelu Academy" plaque in the courtyard is a wooden plaque with gold characters on a black background, which was copied by later generations according to the stone carvings left by the Ming Dynasty. It's a plaque 3.4m long and1.3m wide. This plaque is rigorous in structure and solemn. The font is round and smooth, the brushwork is smooth, the rigidity and softness are combined, the momentum is magnificent, and the style is simple. People can still feel the exquisiteness of Emperor Song Zhenzong's calligraphy from this font, which is a treasure of China's calligraphy art.