OPENER’S SECOND BID AFTER GAME-FORCE (GF)                 
 
After a major (1♠/1♥) opening in first or second position if Responder bids GF in 2♣ or 2♦ or 2♥ there are two polemic approaches for Opener's second bid:
 
A- The most popular way is to show the shape of the hand:
Opener bids his second suit with 54xx or rebids his major suit with 63xx or bids 2nt with 5332. This is normal to show a minimum open with less than 16 hcp. The problem is when Opener makes a reverse bid to show his shape (45xx) without a real strong (16+ hcp) like:
 
 a) Opener => ♠AQ54 ♥AQ765 ♦xx ♣xx
 Opener Responder
   1♥        2♣
   2♠ <= Opener argument is: I am showing where are mine extra values and there are no more reverse because we are in a GF process.
Question: How Responder may know Opener's strength?
In fact, the information of strength is dubious for a partnership that don't have rules to show the strength of Opener's hand in his second bid. This last sequence is a traditional reverse bidding and shows 16-21 hcp.
 
 b) Opener => ♠A10754 ♥Q5 ♦x ♣AQ743
 Opener Responder
   1♠        2♦
   3♣ <= again Responder makes a reverse bid showing 16+ hcp bidding his second suit at level 3. The correct open since 1930 is 1♣ when Culbertson teach us that with 5♠ and 5♣+ and minimum hand we should bid first 1♣ and rebid twice Spades. Of course, within a competitive auction this is difficult, but the information of the strength is more important and should not be distorted.  
 
So, the shape sometimes doesn't clarify Opener's hand strength in his second bid and prioritize the distribution ignoring the importance in give a reliable information of the hand’s strength. This will be a problem to Responder decide in bid or not bid a slam.
 
B- Another way, most used by expert’s players, is prioritize the information of hand's strength and then try to limit the Opener's hand in his second bid even rebidding his major with only 5 cards or waiting to bid his second suit in appropriated moment. They use the 2nt bid to show 16+ hcp and also the second suit bided at level 3.
 
Thus, lets establish rules to disciplinary the information of Opener strength.
 
RULE#1: When a partnership is in GF process each player with a minimum hand (12-15 hcp) should use, if possible, in his second bid the Principle of FAST ARRIVE bidding game as soon as possible.
Opener  Responder
   1♠         2♥
   4♥ <= minimum without splinter (♠KQ10xx ♥10xxx ♦K9 ♣Ax) 
Opener  Responder
   1♠         2♦
   3nt <= minimum without splinter (♠KJ109x ♥AQx ♦92 ♣K109)
 Both examples shows the use of Fast Arrive

RULE#2: After 1♠/1♥ opening and a response GF the rules are:
a) Opener bidding 2nt shows 16+ hcp, even with 6 card major:
Opener  Responder
 1♠/1♥     2♣
  2ST => 16⁺ hcp with stopper in unbid suits - if Opener's suit has 6 cards then at level 3 Opener bids again his major (2nt denies support of 4♣+).
example1
Opener: ♠KQ109xx ♥AQ10 ♦K9 ♣Qx or ♠KQ109x ♥AQ10 ♦K9 ♣Qxx
Opener  Responder
   1♠         2♦
  2ST => 16⁺ hcp with stopper in unbid ♥ and ♣
- if Opener has 6♠ cards that will be bided at level 3
- denies 4♥+ cards or 4♦ cards or 4♣ cards, so distribution should be 5332 or 6322 because denies singleton when bided nt.

exanple2
Opener: ♠AQx ♥AQJ9x ♦x ♣KJ10x
Opener  Responder
   1♥         2♦
   3♣ =>  16+ hcp
- If Opener has less than 16 hcp Hearts should be rebid even with 5 cards
 
b) Opener bids 3nt with 5332 having stopper in the unbid suits with 12-15 hcp:
Opener: ♠K109xx ♥Jx ♦KJ9 ♣AQ9
example3
Opener Responder
  1♠         2♥   
  3nt => Fast Arrive 13-15 hcp promises stoppers in unbid suits and shows balanced distribution

example4  
Opener: ♠KQx ♥QJ10xx ♦xx ♣KQ10
Opener  Responder
   1♥         2♦
  3nt => Fast Arrive 13-15 hcp with stoppers in unbid suits and balance hand  

c) rebidding his 5 cards suit just to limit his hand within 12-15 hcp:
example5
Opener's hand:  ♠AKJ109 ♥J9x ♦x ♣QJ10x
Opener  Responder
 1♠           2♦
 2♠ => minimum (12-15 hcp) can have only 5♠ cards or 6♠+ cards
  Fast Arrive was not applied because:
 - no stopper in unbid ♥;
 - has singleton in Responder suit bided ♦
 can't bid his second suit
 - have 4 cards in ♣ but no 16+ hcp, so no reverse bid.

 example6
 Opener: ♠AJ109x ♥J2 ♦AJ10x ♣Qx 
 Opener  Responder
  1♠          2♥
  2♠ => minimum 12-15 hcp and no support can't bid 3♦ with 12-14 hcp – no sure stopper in unbid suits (♣) - need shows his limited strength rebind Spades
 
d) Opener rebids his major in jumps to shows solid suit: AKQJxx or AKQxxxx 14-15 hcp if more strong then should bid 2nt to show 16-20 hcp
example7
Opener: ♠AKQJxxx ♥93♦A10 ♣xx 
Opener  Responder
  1♠          2♥
  3♠ => this jump in 3♠ ensures 6/7 tricks in Spades and may have additional 1 ace or 2 Kings in case of 7 cards (our Namyats do not allow another ace or 2 Kings)
 
example8
Opener: ♠x ♥AKQxxx ♦K108 ♣Jxx 
Opener  Responder
  1♥          2♣
  3♥ => shows solid 6/7♥ cards up to 15 hcp – Responder now decides final contract
 
e) Opener bids his second suit up the line in level 3 only with 16+ hcp
example9
Opener: ♠KQ10xx ♥Q3♦10 ♣AKQ10x 
 Opener  Responder
  1♠          2♥
  3♣ => shows 16+ points and denies 3 cards support in ♥ having a 5-5 hand we must add 2 points for distribution so Opener’s has 18 points

example10
Opener: ♠x ♥AKQxxx ♦K108 ♣AJ9x 
Opener  Responder
  1♥          2♦
  3♣ => shows 16+ points
 
f) Opener bids his second suit up the line in level 2 with 12-15 hcp
example11
Opener: ♠Qxxx ♥AQxxx ♦K108 ♣x 
Opener Responder
  1♥         2♣  
  2♦ => 12-15+ hcp and must bid 3♦ cards suit avoiding false Spades reverse  

example12
Opener: ♠108543 ♥AKQJx ♦Q8 ♣x 
Opener Responder
  1♠         2♣  
  2♥ => 12-15+ hcp and shows 5♠+-4♥+ (can’t opening in Hearts)

g) Opener support to Hearts using Fast Arrive versus slow arrive
example13
Opener: ♠KQ109xx ♥Q10x ♦K9 ♣Qx 
Opener  Responder
  1♠          2♥ 
  4♥ =>   minimum (12-14 hcp) Fast Arrive support with 3/4 cards 

example14
Opener: ♠KQ109xx ♥AQ10 ♦K9 ♣Qx
 Opener  Responder
   1♠            2♥   
   3♥  =>    slow arrive means 16⁺ hcp and slam interest
                   4♥  => no cuebid - so minimum response hand

h) Opener supports Responder's minor at level 3 with 4+ cards and 12-15 hcp
Opener Responder
  1♠/1♥     2♣
     3♣ => minimum - 4 cards support (exception 3 cards with 2 top honors)
example15
Opener: ♠Q109xx ♥A10x ♦J9 ♣KQx
Opener Responder
  1♠       2♣
  3♣ => minimum 12-15 hcp

example16
Opener: ♠Kx ♥AJ10xx ♦J9 ♣K983
Opener Responder
  1♥       2♣
  3♣ => minimum 12-15 hcp

i) Opener supports Responder's minor in jump to level 4 showing 4+ cards support with a top honor and 16+ hcp – slam interest
example17
Opener: ♠A10 ♥AK109x ♦Q9 ♣KJxx
Opener Responder
  1♥       2♣
  4♣ => strong 4♣+ support with 16+ hcp – Responder should cuebid or RKB

example18
Opener: ♠AKJ109 ♥Kx ♦KJ93 ♣Kx
Opener Responder
 1♠        2♦
 4♦ => strong 4♦+ support with 16+ hcp – Responder should cuebid or RKB

example19
Opener: ♠x ♥AK10xx ♦KQ943 ♣K3
Opener Responder
  1♥       2♦
  4♦ => strong support 16+ hcp – Responder bidding 4♥ is to play denying 2 aces and bidding 5♦ is sign-off denying aces in unbid suits else Responder must cuebid

J) Opener jumping after GF is splinter not showing strong 2 suits
example20
Opener: ♠AKJ109 ♥x ♦KJ93 ♣Kxx
Opener Responder
  1♠       2♦
  3♥ => splinter singleton ♥ with support 4♦+ cards - 12+ hcp  

example21
Opener: ♠KJx ♥AK10xx ♦3 ♣K1093
Opener Responder
  1♥       2♣
  3♦ => splinter singleton/void in ♦ 12+ hcp

example22
Opener: ♠KQJxx ♥K10xx ♦3 ♣A109
Opener Responder
  1♠       2♥
  4♦ => splinter singleton/void in ♦ 12+ hcp

Negative example23
Some players after a 2/1 GF in this difficult sequence “1♦ response 2♣”
looking for show their suits do wrong reverse bid with 12-15 hcp
 
 Opener Responder
   1♦         2♣
  2♠/2♥ <= in fact this bid needs 16⁺ hcp for all partnership that play reverse
                       
We emphasize that the information of Opener's strength defined by his second bid is vital to Responder take decision in stop at game or try slam.
 
 Reinforcing:
 
 - in 2/1 the Principle of FAST ARRIVE is a useful tool to show hand's strength, so after a GF established, Opener and Responder should go to game as soon as possible or bid slowly to show a good hand (16+ hcp);
 
 - One common rule to limit Opener's hand is the rebid of his major 5 cards at level 2 showing a minimum hand 12-15 hcp;
 
 - After 1♥ opening and responses 2♣ or 2♦ Opener's bids in 2♠ shows a reverse hand with 16+ hcp;
 
 - If Opener's first bid is 1♠ then after a response in 2♥ a second bid in 3♣ or 3♦ promises 16+ points, so Opener with 54xx and less than 16 hcp must rebid 2♠ waiting that Responder bids his minor to then maybe supports partner’s minor;
 
 - Opener's second bid in 2nt promises 16+ hcp with distribution 5332 or 6322 and stoppers in unbid suits;
 
 - Responder's second bid follow also FAST ARRIVE Principle and a support in a major opening bided at level 3 is more strong than bided at level 4.
example24
 Opener Responder
   1♠       2♦
   2♥       ?
              3♥ => 16+ hcp
              4♣ => splinter singleton Clubs 12+ hcp
              4♥ => 12-15 hcp without splinter