Correct contract bridge / by E.V. Shepard ; including the official Laws of contract bridge adopted by the Whist Club, New York, and by all the leading clubs in America.

200 CORRECT CONTRACT BRIDGE
A has 6~4 honor tricks, with an ideal distribution
for a double. Also A can add at least i Y2 trump
tricks to his values (>2 trick for 4 trumps and one
trick for ability to ruff clubs once), a total probable
assistance for any response of 7 Y4 tricks. Aside
from honor tricks, ordinarily A may reasonably expect to find his partner with a i-card suit, which in
itself counts i 2 probable tricks, as more often than
not the opposing 4 trumps will fall in two rounds.
With this in mind A may reasonably expect his
partner to go game at either major suit, even if his
partner holds no more than a single honor trick. As
the cards lie, whether B or Y happened to be A's
partner, game should result as a response to A's
informatory double.