The Sun Four-Wall Rules · American four-wall
Rule 3 Toss for first hand
HistoricalThe Sun Four-Wall Rules, 1889 (historical)
When a match is made, be it double or single, the players shall toss for the first hand, the winner to have one hand only in the first inning.
Mentioned here
How this rule changed
See the wording of this rule in every rulebook, with the changes marked.