Eta is a trump asking bid in a potential trump suit when Responder is known to have a 4-card holding in that suit. Because none of the responses have to deal with Responder's length in the suit, greater precision is able to be given about their exact cards, including whether or not they have the Jack. The use of Eta always agrees the suit as trumps (Like Gamma) and Opener is assumed to have at least a 4-card holding themselves (but see Positive 4441's below). The Responses to an Eta Ask are indistinguishable from those for a Length Known Gamma when the known suit length is 4-card.

When is a Bid Eta?

A bid is Eta in the following situations:
  • If Responder has shown an 12+ point 4441-shape hand by jumping at the 3-level in the suit below the singleton over a 1 Opening, the first bid in one of their 4-card suits is Eta, but if Opener makes a Beta Ask first and the first bid in one of Responder's 4-card suits is at game level, then this is a sign-off rather than Eta.
  • If Responder has shown an 8-11 point 4441-shape hand by jumping to 2, 2 or 2NT over a 1 Opening then an immediate bid in one of their 4-card suits below game level is Eta, but see Positive 4441's below for the special scale after 1-2NT..
  • After any 2 Stayman Enquiry, if Opener shows a 4-card Major at the 2-level, then an immediate bid of the other Major at the 3-level is Eta in the Major Opener has shown, eg: 1NT-2-2-3.
  • In 2 sequences where Opener shows a 4-card Major, then an immediate bid at the 3-level in the other Major is Eta in Opener's Major (See Two Clubs Openings).
  • After a 2 Opening, a 2-way Transfer by Responder and Opener has shown a singleton in the Transfer suit, any new suit bid by Responder (showing 14+) is Eta
  • In the Complex System, Where Responder shows any 11+ hand and Opener then shows any 4441 hand, Eta Asks are available below game level

Responses to Eta

The responses to Eta are as follows:
Normal Scale
  1. : Jxxx or worse
  2. : Qxxx (ie: One Top Honour)
  3. : QJxx (ie: One Top Honour & the Jack)
  4. : KQxx (ie: Two Top Honours)
  5. : KQJx (ie: Two Top Honours & the Jack)
  6. : AKQx (ie: Three Top Honours)
Ambiguous 4441 Scale
After a 1 Opening, when Responder has shown a 4441-shape hand, there are some situations when Responder has shown a "Major Suit Singleton" or a "Minor Suit Singleton" rather than identifying the singleton suit precisely. These are:
  • 1-2NT (Showing a Minor Suit Singleton)
  • 1-(1)-2 (Showing a Major Suit Singleton)
  • 1-(1)-2NT (Showing a Minor Suit Singleton)
In these circumstances, if Opener makes an Eta Ask in the rank where Responder might have a singleton, the responses to Eta are as follows:
  1. : Singleton
  2. : Jxxx or worse
  3. : Qxxx (ie: One Top Honour)
  4. : QJxx (ie: One Top Honour & the Jack)
  5. : KQxx (ie: Two Top Honours)
  6. : KQJx (ie: Two Top Honours & the Jack)
  7. : AKQx (ie: Three Top Honours)


Suit Agreement

Given that an Eta is effectively a "length-known" Gamma, similar rules apply to trump agreement as they do for Gamma:


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OCP System Change Log
Cancelling Suit Agreement after Gamma or Eta (14-Oct-2021)
This is a clarification rather than a genuine change:
  1. After any use of Gamma or Eta, the general position is that the mere use of those Asking Bids agrees the suit as trumps. However...
  2. If the initial response shows No Top Honour in the suit and the next bid up is a bid in No Trumps, then that bid in No Trumps cancels out the suit agreement, is not Relay Beta, and is rather HoC or "to play".
  3. If the suit agreed is a Minor suit, or any time that a bid in No Trumps is made immediately over the Gamma or Eta response that is not a relay, then that bid in No Trumps is HoC or "to play" (depending on the level) unless it is obviously strong or invitational.
  4. This applies to all situations where Gamma or Eta is used, including when a 2-way transfer has been made after a 2 Opening.
Interference over 2 Openings (07-Apr-2017)
Completed documentation of interference immediately after Responder makes a 3-way Transfer, and also immediately after Opener either completes or denies a 2-way Transfer. This had never been fully documented before, so not repeated here. See the section on Interference on the Simple 2 page.
Responses to Two Diamond Opening (16-Dec-2016)
This is a major overhaul of the Simple System 2 Opening:
  • The 2 Response and continuations are largely unaffected, except that some hands that would originally have bid 2, now do something else.
  • The 2 Response now shows any 0-4 single-suited hand. Opener bids 2NT with a lower-range hand, but Oliver's Twist at the 3-level with an upper-range hand.
  • The Responses from 2NT through to 3 are now all 2-way transfers, showing either:
    1. 0-4 HCP with any any touching 2-suited hand or even 4333 or 5332 where the suit above their 4+-card suit is at least 3-card in length, or
    2. 14+ with any 2-suited hand, normally transferring into the cheapest or lower-ranking suit, but optionally into the high-ranking.
    Opener completes the transfer with a 4-card holding in the transfer suit and relays in the suit above with a singleton in the transfer suit. If Opener bids the transfer suit, Responder normally passes with any 0-4, but with 14+ treats the bid as Gamma. If Opener skips the transfer suit, again Responder normally passes with 0-4, but with 14+ bids their second suit as Eta (Cheapest bid in NT's normally is Gamma in the suit Opener actually bid.
  • For full details, please see the re-written 2 page.
Reorganisation of 4441 Positives (07-Feb-2014)
Prior to this change, OCP used the Classic Precision semi-positive responses of 2, 2, and 2NT, and also used the Impossible Negative to show lower-range 4441 positives. This change scrapped all of that, so that 1-1 was always showing 0-7 HCP. The semi-positive responses were binned, and in their place:
  • 1-2 showed 8-11 hcp with 4144 shape (singleton Heart)
  • 1-2 showed 8-11 hcp with 1444 shape (singleton Spade)
  • 1-2NT showed 8-11 hcp with 4414 or 4441 shape with a Minor suit singleton.
  • 3-level suit responses to 1 all showed 12+ 4441 hands, bidding the suit below the singleton.
Over all of these Eta Asks by Opener were the norm. A special scale for Eta was created over the 2NT response which has an extra step showing that Opener had hit Responder's singleton.
Eta After Stayman (07-Apr-2013)
In the interests of symmetry and consistency, the sequence ...1NT-2-2-3, which had been treated as natural and invitational in Hearts, will now be treated as Eta in Spades. This will mirror the sequence ...1NT-2-2-3, which was always Eta in Hearts.