Che (Cyrillic) in the context of Koppa (Cyrillic)

Koppa (Ҁ ҁ; italics: Ҁ ҁ) is an archaic numeral character of the Cyrillic script. Its form (and modern name) are derived from some forms of the Greek letter Koppa (Ϙ ϙ).

Koppa was used as a numeral character in the oldest Cyrillic manuscripts, representing the value 90 (exactly as its Greek ancestor did). It was replaced relatively early around 1300 by the Cyrillic letter Che (Ч ч), which is similar in appearance and originally had no numeric value. Isolated examples of Ч used as a numeral are found in the East and South Slavonic areas as early as the eleventh century, though Koppa continued in regular use into the fourteenth century. In some varieties of Western Cyrillic, however, Koppa was retained, and Ч used with the value 60, replacing the Cyrillic letter Ksi (Ѯ ѯ).