What do you mean, both are good at calligraphy?

In calligraphy, "good" refers to the calligrapher's expertise in calligraphy style and techniques.

The so-called "monopoly" has two meanings:

1. A calligrapher has something unique that others don't. (Take the lead, no one can compare)

A calligrapher has only one specialty. (single technology or specialization)

"Two-pronged" also has two meanings:

1, inclusive, with many specialties;

2. Specialize in one aspect and give consideration to other aspects at the same time.