When it was originally established in 1973, the British Darts Organisation (BDO) adopted the oche length the National Darts Association of Great Britain (NDAGB) had first set up in its rules in 1954.
However, after the founding of the World Darts Federation (WDF) in 1977, its member countries looked to agree a ‘world’ standard length of throw, a happy medium between the NDAGB length (7 feet 6inches) and that of the News of the World (8 feet). Logically this would surely have meant 7 feet 9 inches but instead of setting the standard at that, the WDF came up with 7 feet 9¼ inches.
But why?
For many years it was believed and blogged that 7 feet 9 inches did not ‘translate’ into metric (metric being all the rage back in ‘77) but 7 feet 9¼ inches (2.37metres) did, thus explaining the strange length of oche. I included this ‘fact’ in a Unicorn blog some years ago, believing it to be true but then some wise person responded pointing out that 7 feet 9 ¼ inches did not translate exactly to 2.37 metres but 2.368852 metres.
On putting this to the WDF the truth was finally revealed. The measurement was never intended to be an ‘exact’ equivalent in metres but a compromise. At the WDF Meeting at Wembley in 1977, where the very first WDF World Cup was discussed, the distance of 2.37m was adopted as the official WDF Standard. It was proposed (it is believed by the Swedish delegate) that the 7 feet 9¼ inchesbe adopted in its’ metric equivalent which happened to be extremely close to 2.37 metres. This was seconded and approved unanimously by all countries present.
It had to be a compromise. After all, it could hardly be expected that tournament organisers would, or even could, measure out a 2.368852 metre oche!
[By the way, for those who appreciate such comparisons, the difference between 2.37 metres and 7 feet 9¼ inches is almost exactly the thickness of a sheet of Standard A4 printer paper.]
Months after the WDF meeting in 1977 the 7 feet 9 ¼ inches throw-line was adopted as world standard for all major darts tournaments and this continues to be the case today.
It should be noted that the length of the oche has nothing whatsoever to do with a brewery named Hockey. No such brewery ever existed.
© 2005-2020 Patrick Chaplin
With thanks to David king at Darts501.com.
Dr Patrick Chaplin 
Harold,
Thanks for your question received via my website.
The width of the double segments on an elm dartboard would usually be one half of an inch but, because these darts were handmade and varied in size from area to area and the wire varied in thickness, the actual playing area would be less.
Best wishes,
Patrick
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