Contract Bridge (now just bridge) have many contributors but there are high emphasis for Ely Almon Culbertson (1901-1955) that founded "The Bridge World Magazine" in 1929. As editor he developed bridge principles in many articles, as writer he elaborated the first bridge system with "Blue Book" in 1930 and "Contract Bridge Complete" in 1936, using a method for valuation hand's strength based in "honour tricks" (A=1 AK=2 AQ=1,5 Kx=0,5  AJ10=1,5 AJx=1,25 KJx=0,75 QJx=0,75 KQx=1,5 Qxx=0,25 J10x=0,25 ...) and introduced the conceptions of forcing and sign-off bids during the auction.

In the 6th editon of his book "Contract Bridge Complete", Culbertson, due to many players had difficulty in add differents fractions, replaced his valuation method of "honour tricks" by "point count" that was introduced by Bryant McCampbell in 1915 based in "high cards points" (hcp) where A=4 K=3 Q=2 J=1. Milton Work published this scale only in years 20.

Culberton with innovative articles and new ideas stimulated also in the formulation of others systems like in England the Acol system using a 1nt weak open (12-14 hcp) and semi forcing open 2/2 (6 cards and 16-18 hcp). But in 1935 the Vienna System created by Paul Stern - the captain of Austrian team - using, initially, Bamberger points count (A=7 K=5 Q=3 J=1) introduced a inovative successful bidding structure with the use of artificials bids that influenced years after the formulation of others system like the Italians systems and The Precision System - won the European ope

championships in 1936 and in 1937. Also won the first world championess defeating in the final match Ely Culbertson's American team in a challenge match in 1937, thus starting the Culbertson decline.

In 1937 ACBL - American Contract Bridge League was founded and is now the largest bridge's league in North America with more than 165,000 members in USA having over 3.5 millions tables each year in more than 3 thousand bridge clubs and also online tourneys with more than one million tables each year.

Points Count
In 1904 Edmond Robertson published his point count where A=7 K=5 Q=3 J=2 10=1 and it appers to be more acurate because the 10 is a important cards in many configurations, but in the Bamberger points count the 10 was not include and the deck in Bamberger stay with 64 high card points and that imply the need of 39 high card points (hco) for a game in no-trump or in a major suit and 52 hcp for small slam. In 1927 George Reith change Edmond Robertson's scale to A=6 K=4 Q=3 J=2 10=1 to maintain proportionality in the points. In fact in Milton Work published scale the value of ace is around 4.25, the king around 3 and the queen less than 2, but the simplicity of the scale 4321 is evident.

In fact we should not look only for hcp but also for adjustment in the hand's distribution and for middle cards configurations like J109x has more value than J854 or Q10x was more value than Q82 or K109 has more value than K32 or A1098 has more value than A743. Futhermore for a valorization more adequate we should not thinking only in hcp but using also our perception of losers and in a competitive bidding this is more important to hand's revaluation.

Having long suit with rare distribution type 6-4 or 7-4 our hand's valuation should not be based in hcp but in losers. Thus, hcp is important for balanced hand and then the 10 became a important card. However the Milton Works's points count became dominant also for players of Vienna System that abandoned the Bamberger scale to use the deck with only 40 hcp where with 25-26 hcp we should try game in 3nt 4 4 and try Slam with 32-33 hcp. Of course advancers players use their experience looking for middle cards and hand's distribution to decide between stop in a partial score or go to game. A hand with 4333 distribution is a high factor to any player became pessimist and stop the bidding.

In 1936 Charles Henry Goren (1901-1991) published his book "Contract Bridge Complete using "point count" with additional distributional points for hand valuation - during 1950 thru 1962 he became the new bridger leader writing many bridge books, but then his system using opening majors with 4 cards and all open 2 as strong was overcomed by more agressive bidding systens like Roth-stone systems or systems with major 5 open and weak 2 open.

The Point Count Adjust
Initially Goren propose the follow adjustment in points
Opener hand:
- void suit plus 3 points
- each singleton plus 2 points
- each dubleton plus 1 point
Responder hand after 4 cards fit in partner's open suit:
- void suit plus 5 points
- each singleton plus 3 points
- each dubleton plus 1 point

The modern valuation of hand take in consideration the length
Opener hand:
- each suit with 5 cards add 1 point (need 2 top honors)
- each suit with 6 cards add 2 points (need A or KQ at top)
- each suit with 7 cards add 3 points (need A or K at top)
- hand with distribution 4333 -1 point
- hand with 4 aces add 1 point
- hand with no aces -1 point
Responder hand having 4 cards fit in partner's open suit:
- void suit add 5 points
- each singleton add 3 points
- each dubleton add 1 point

Honors Adjustments
- concentration of honors in a suit increases the hand's value
    AKQ54 93 83 10986 versus  Q7654 A4 K3 10642
- honors in long suit increases the value of the hand
   AK10654 3 83 A1096  versus 1076543 A AK 10963 
- honors in short suits decreases the value of hand
- intermediate cards increases the value of the suit
   KQ1098 versus KQ765   or  AJ1092 versus AJ753

The understanding of Points Count is not the most important conerstone to have success in the bridge table. Another conerstone is the use of a strong bidding system that allow us to exchange realible information between partners and Opener's second bid must priorize the information  about the strenght of the hand and same for Responder's second bid. In fact some systems, like Precision, limit opener's streght bid with great success because Responder can pass with 8 hcp knowing that the chances for game are very low and this makes hard for opponent's reopen.

In 1953 the great bridge champion 16 times, Alvin Leon Roth (1914-1992)published with his partner Tobias Stone (1919-2012) the Roth-stone system introducing new ways to show the caracteristics of Opener's hand and Responder's hand like five-cards major, nt forcing after major open, negative double (sputnik), unusual nt overcall, splinters, 1 major response 3 as GF with 4 cards support and many others specials bids that were used by the future Two Over One Game Force System (2/1). 

In the sixties a new popular american system started to open majors with 5+ cards and use weak open of 2/2/2. This was cristalized as "Standard American Yellow Cards" (SAYC).

In meantime The World Bridge Federation was founded in 1958 and the first Team Olympiad occured in 1960. Today WBF memberships consit of 103 National Contract Bridge Organizations with about 700.000 affiliated members and so is responsible by world championship competitions:
a) Bermuda Bowl - since 1950 is the world championship 44 realizations;
b) Venice Coup - since 1974 is the woman's world championship (23);
c) Senior Bowl - since 2001 is the senior's world championship (11);
f) Youth Teams Championship - since 1997-  already 17 realizations.

In 1962 Richard Lycoln Frey (1905-1988) suggest to ACBL a project for an Bridge's Enciclopedea to answer any question of bridge and after 18 months, in 1964, the first edition of The Official Encyclopedia of Bridge was published and in 1994 the 5th edition was published.

In early 70's scientif system using some ideas of Roth-Stone, create by experts players like Richard Walsh, became in the 80's known by the name of "Two Over One Game Force" (2/1) due to the book of Max Hardy. Now 2/1 is one of the most popular system used by advanced players. Of course the italians systems since 1950 and the Precision system since 1969 are up to date and used by expert's bridge players in competitive events.

In terms of popular system, SAYC and 2/1 are the most used system followed by UK English Standard Acol system. Beginers and intermediates players make the use of SAYC and then evolve to 2/1 after gaining a better understanding of bridge's game with fixed partnership.

SAYC and 2/1 have very differents conceptions for the bidding, but in both systems Opener and Responder need inform hand's strength during the auction as a priority and this is the fundamental conerstone for a system success.

Summary: Bridge is a sport and World Bridge Federation is recognised by International Olympic Committee. Bridge is enjoyed by tens of millions of people throughout the world. Finally, play bridge is health for your mind.

====================================== In Construction

Lets explain some differences between SAYC and 2/1:

A)
Opener Responder
 1/1   1nt  <= playing SAYC Responder bidding 1nt limited his hand in the range of 6-9 hcp and Opener with 5332 should pass not giving oportunity to Responder shows his possible long 6/7 cards suit, but in 2/1 the response of 1nt shows a hand limited in the range of 5-11 hcp and it is forcing after a major open, so Opener must bid again giving opportunity to Responder sign-off in a long suit, or also make a invitation when has 10-11 good hcp.
The 1nt response forcing is a huge  improvement in bidding system and 2/1 have incorporated that from the famous Roth-Stone system.
Example:
Opener      : AQ765 Q43 Q3   A106
Responder: 82 K7 KJ10954 854
Opener Responder     Opener Responder
  1         1nt SAYC      1         1nt 2/1
 pass                           2         2
.............................    pass           
Playing in nt if the killed lead is J then, as we see, declarer will make 1 trick in Clubs, 1 trick in Hearts, 1 trick in Diamonds and maybe 2 tricks in Spades for down 2 in 1nt, but playing in 2 declarer will only lose 1 Hearts, 1 Diamons, 0,5 Spades and 2 Clubs making 2 or 3 Diamonds.

B)
In Sayc after the open in 1, and no interference from opponents, the response of 2, 2, 2 shows 10+ hcp and it is forcing until 2nt or 3

/3

if Opener have only 12-13 hcp and Responder have 10-11 hcp.
 

Opener Responder      SAYC      1        2  2nt <= 12-13 hcp ............ pass <= 10-11 hcp Opener Responder      SAYC  1         2  3 <= 12-13 hcp ........... pass <= 10-11 hcp

Opener Responder          SAYC    1        2  2nt <= 12-14 hcp ............ 3nt <= 13-15 hcp Opener Responder        SAYC  1         2  4 <= 14-17 hcp ........... pass <= 10-15 hcp

The Lemma in Sayc is: "MORE HIGH YOU BID MORE STRONG YOU ARE"
The Lemma in 2/1 is: "FAST ARRIVE - AFTER GF ESTABLISHED IF A PLAYER BID GAME QUICKLY HIS HAND IS LIMITED UP TO 14 HCP, BUT IF HE BIDS SLOWLY HIS HAND IS 15+ HCP"

Opener Responder         2/1   1        2  <= 12+ hcp  2nt <= 16+ indefine hand ............ 3nt <= 12-14 hcp Opener Responder  1         2  3 <= 16+ hcp ........... 4 <= 12-14 hcp

Opener Responder            2/1   1        2  <= 12+ hcp  3nt <= 12-14 hcp ............ pass <= 12-17 hcp Opener Responder  1         2  4 <= 12-14 hcp ............ pass <= 12-17 hcp

Opener Responder        SAYC   1        2 <= 10+hcp   2         ? ..... 2 <=not forcing 2 cards ..... 3 <= invitation 3 cards ......4 <= 13+ hcp 3+ cards Opener Responder  1         2  2          ? ....... 2nt <= invitation 11-12 ....... 3nt <= 14-17 hcp .......  3  <= sign-off  10-11 .......  3  <= invitation 11-12 .......  4  <= 13-17 hcp

Opener Responder            2/1   1        2 <= GF 12+ hcp   2        ? ............ 2 <= 3 cards 16+ hcp ............ 4 <= 3 cards 12-15                           Fast Arrive ............ 2nt <= 16+ hcp ............ 3nt <= 12-15 hcp                            Fast Arrive Opener Responder  1         2 <= GF 12+ hcp  2         ? ........... 3 <= 16+ hcp ........... 4 <= 12-15 hcp                          Fast Arrive

C)
In 2/1 after an open in 1 wuthout interference, the response of 2, 2, 2 shows 12+ hcp and are game-force (GF) - this is the reason for the system name be "two over game force";
- Similar occurs after 1 open and response in 2 or 2;
- But after an open in 1 the response in 2 could be played  as GF or as a limited hand with long Clubs suit if Responder rebids Clubs suit. Thus this must be an agreement by partnership. We recommend as GF,

In SAYC after 1 open after a response in 2, 2 or 2 if in his second bid Responder rebids his suit then this is sign-off.

D)
When we open in a major suit there are some conventions to establish GF like the Splinter and Jacoby 2nt and these conventions are now used in Sayc and 2/1.
 
In SAYC after 1 open there are a problem to establish GF because if we raise to 2 this is a limited support with 6-9 hcp and if we raise to 3 this is a limited support with 10-11. So there are no good way in bid a hand like: AK Kxx xx KQ8762. Same occurs after 1 when Responder has a strong support to Diamonds.

In 2/1 tt is used the Inverted Minors  convention that solve this problem.
So in 2/1 after 1 the response 3 (limit bid) shows 5-9 hcp with 5+ cards support but the response 2 shows 10+ hcp and after Responder's second bid if he rebids his minor open then he limits the hand in 10-11 hcp but if he bids something else then he show 12+ hcp. Same after 1 open and the responses 2 or 3.

E)
Another convention used by Sayc and 2/1 partnership is NMF - New Minor Forcing that allows Responder search for support of 3 cards in his major after the sequence:
Opener Responder
1minor  1major
  1nt      2 in the other minor <= nmf

F)
There are many books teaching 2/1 that after a GF response at level 2 Opener must show his shape and there are no more reverse - this is not our approach for 2/1 - we consider that Opener must inform the strength of his hand 12-14 or 15+ hcp, so a reverse bid shows strength not shape:
Opener Responder
    1         2
 2/2 <= is this a reverse or "who knows ?"
Operner Responder
    1         2
    2    <= is this a reverse or "who knows ?"
Well, it is really more simple bid our suits, but Responder must know how strong Opener's hand is to try possible Slam or Grand Slam and so this aproach in inform the shape of the hand don't give this clear answer to Responder that is now the captain of the final contract to take the best contract decision.
Example:
Opener1      : AJ65 AQJ43 8 J54
Opener2      : AKJ8 AKQJ4 8 1054
Responder1: Q1072 7 AKJ109 A42
Responder2: Q1072 7 AKQJ9 QJ2
Operner Responder
    1         2
    2         3
    4          ? 
should Responder pass?
First Responder must know if that was a reverse or no;
Responder should understand that Opener does not have control in Clubs;
Thus Responder having A must go to Slam with hand1 that is more weak than hand2, but must pass with hand2 without Clubs control.
Of course if Opener not promise reverse then Responder must pass in both cases.

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Conclusion: A good system like 2/1 need also some conventions and good communication between partnes to inform about the hand.

Thus any partnership must study a system, like 2/1 with a specific approach, and the selecteds conventions integrated in the system.

Many conventions are played by most partnership, so if you and your partner knows what opponents are bidding that will help partnership in defense or in the play of the hand.

The evaluation of a hand isn't just High Card Points, but also perception of hand's distribution, so in a competitive bidding when opponents also inform their suit and their fit we can use these information in the Law of Total Tricks as a guideline to STOP, DOUBLE or BID at the right level!
Read Law-Total-Tricks;