Title: History of cricket
Content:  During most of the 19th-century standard overs were made up of four deliveries. In 1889 five-ball overs were introduced in first-class cricket, with a move to generally use six-ball overs in 1900. In the 20th-century, eight-ball overs were used at times in a number of countries, primarily Australia, where eight-balls were the standard over length between 1918/19 and 1978/79, South Africa and New Zealand. Since the 1979/80 Australian and New Zealand seasons, six balls per over have been used worldwide, and the most recent version of the Laws only permits six-ball overs.
Title: Over (cricket)
Content:  to the toss. In practice, the number of balls was usually stipulated in the playing regulations governing the match being played. Although six was the usual number of balls, it was not always the case. From the 1980 code onwards, law 17.1 was amended to read, "The ball shall be bowled from each end alternately in overs of 6 balls". Balls per over In England In Australia In South Africa In New Zealand In Pakistan In India, West Indies, Sri Lanka, Zimbabwe, Bangladesh, the United Arab Emirates (venue, not host) and Ireland all Test matches have been played with six ball overs.
Title: Laws of Cricket
Content:  since the 1771 incident and the length was specified as the current 38 inches in 1835. ; The weight of the ball is unchanged since 1774. Its circumference was ruled as between nine and 9.25 inches in 1838; this was reduced to the current measure in 1927. ; There were four balls an over in 1744 and this did not change until 1889 when a five-ball over was introduced. In 1900, the over was increased to six balls. The over in Australia and some other countries has at times varied from the English but, from 1979, the six-ball over has been worldwide. 
Title: Over (cricket)
Content:  all Test cricket has been played with six balls per over. However, overs in Test cricket originally had four balls per over, and there have been varying numbers of balls per over around the world up to 1979/80, generally the same as the number of balls per over in force in other first-class cricket in that country. Prior to the Laws of Cricket (1980 Code), law 17.1 (Number of balls [in the over]) did not explicitly specify the number of balls to be bowled in an over, but merely stated that the number of balls should be agreed by the two captains 
Title: History of cricket
Content:  In the 1960s, English county teams began playing a version of cricket with games of only one innings each and a maximum number of overs per innings. Starting in 1963 as a knockout competition only, limited-overs cricket grew in popularity and, in 1969, a national league was created which consequently caused a reduction in the number of matches in the County Championship. The status of limited overs matches is governed by the official List A categorisation. Although many "traditional" cricket fans objected to the shorter form of the game, limited-overs cricket did have the advantage of delivering a result to spectators within a single day; it did improve cricket's appeal to younger or busier people; 
Title: Cricket
Content:  The Laws state that, throughout an innings, "the ball shall be bowled from each end alternately in overs of 6 balls". The name "over" came about because the umpire calls "Over!" when six balls have been bowled. At this point, another bowler is deployed at the other end, and the fielding side changes ends while the batters do not. A bowler cannot bowl two successive overs, although a bowler can (and usually does) bowl alternate overs, from the same end, for several overs which are termed a "spell". The batters do not change ends at the end of the over, and so the one who was non-striker is now the striker and vice versa. The umpires also change positions so that the one who was at "square leg" now stands behind the wicket at the non-striker's end and vice versa.
Title: Cricket
Content:  Cricket entered a new era in 1963 when English counties introduced the limited overs variant. As it was sure to produce a result, limited overs cricket was lucrative and the number of matches increased. The first Limited Overs International was played in 1971 and the governing International Cricket Council (ICC), seeing its potential, staged the first limited overs Cricket World Cup in 1975. In the 21st century, a new limited overs form, Twenty20, made an immediate impact. On 22 June 2017, Afghanistan and Ireland became the 11th and 12th ICC full members, enabling them to play Test cricket.
Title: History of English cricket (1816–1863)
Content:  During the post-war years, there was a discernible shift towards the adoption of roundarm bowling and questions about legalisation of roundarm dominated the sport for thirty years. At the end of the period, bowling reached the final stage of its evolution as overarm bowling began with the same sort of controversy that had accompanied the introduction of roundarm. But this time the controversy was short-lived and overarm was rapidly adopted and legalised between 1862 and 1864. The roundarm issue was already controversial enough in 1816 for MCC to amend the Laws of Cricket to prohibit it: "The ball must be bowled (not thrown or jerked), and be delivered underhand, with the hand below the elbow. But if the ball be jerked, or the arm extended from the body horizontally, and any part of the hand be uppermost, or the hand horizontally extended when the ball is delivered, the Umpires shall call "No Ball""
Title: Twenty20 International
Content:  Cricket itself was probably first played in England in the Late Middle Ages, but it did not rise to prominence until the eighteenth century. A set of laws were drawn up in 1744, and the game achieved a level of relative standardisation by the late nineteenth century. One-day cricket was trialled in 1962, and the first domestic tournament played the following year, and in 1971, England and Australia contested the first One Day International. The match consisted of one innings for each side, with 40 eight-ball overs. In the 1990s, a number of countries were exploring the possibility of a shorter game still: in New Zealand, Martin Crowe developed Cricket Max, in which each team bats for 10 eight-ball overs, while in Australia they considered an eight-a-side contest they dubbed "Super 8s". At the same time, the England and Wales Cricket Board (ECB) conducted consumer research, and proposed the idea of a 20 overs-per-side contest, which would last for about three hours. The first match was played in 2003 between Hampshire and Sussex.
Title: Pro Cricket
Content: Overs consist of five balls instead of six. ; Bowlers could bowl up to five overs each (25% of the total), meaning only four bowlers are needed rather than five. The format of the games were 20 overs a side, similar to Twenty20 cricket. However, there were two major changes from the rules of cricket used elsewhere: Additionally, the league used a "designated hitter" rule, in which teams consist of 12 players, 11 of whom field and 11 of whom bat. This was similar to such rules existing in some domestic List A cricket competitions. All of these changes were designed to shorten 

Question: when did cricket go to 6 ball overs?
Answer: 1979/80.
Since 1979/80.