Economou Two Hearts

An opening of two hearts shows

(a) 5-11 HCP and at least 5 spades OR
(b) Weak hand with spades+other 2 suits (i.e., shortness in hearts) OR
(c) Weak in spades but strong balanced hand.

Response 2S non-forcing relay to spades
2NT forcing relay - with a weak hand, opener bids cheapest second suit, with stronger hand bids at 3 level.