What is Four tones (Middle Chinese)?

The four tones of Chinese poetry and dialectology are four traditional tone classes of Chinese words. They play an important role in Chinese poetry and in comparative studies of tonal development in the modern varieties of Chinese, both in traditional Chinese and in Western linguistics. They correspond to the phonology of Middle Chinese, and are named even or level , rising , departing or going , and entering or checked. , an important concept in poetic tone patterns.] They were reconstructed as mid , mid rising , high falling , and mid with a final stop consonant respectively. Due to historic splits and mergers, none of the modern varieties of Chinese have the exact four tones of Middle Chinese, but they are noted in rhyming dictionaries.