楷書 (Jp: kaisho; Ch: kaishu)
The next step in calligraphy’s innovation was the development of a standard script. Standard or regular script is used when clarity is of the utmost importance, such as for formal documents, books, etc. It was also the script most commonly used for mass printing, which was first invented in China around 800 CE, while movable type developed around 1000 to 1100 CE.
Though standard script’s crisp lines would seemingly require less skill, such regularity requires a steady hand and an understanding of how much ink to load onto the brush to achieve a consistent stroke—any error or irregularity would be glaringly obvious.