Straddle Calendar (Diagonal)

DSTDCDSTDC-E2_E1-X(E2)_X(E1)

Buy far-dated straddle at strike A, sell near-dated straddle at strike B.

Near Expiry (E1)

Far Expiry (E2)

Strike X1 (low)

Strike X2 (high)

Diagonal straddle calendar — adds a bias along the smile to the standard straddle calendar.

Pick two expiries and 2 strikes to build the combo.