Richard Guy has shown that there are six points in the plane—no three collinear,
no four cocircular—such that all interpoint distances are rational.

> Guy, Richard. *Unsolved Problems in Number Theory*. Vol. 1. Springer, 2004.
D20. Six general points at rational distances. p.185ff:

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![GuyFig14b][1]
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My question is:

> Q. Is it known that six is the maximum possible? Or have examples been found in the
intervening decade that supersede Guy's result?

**Update**. This question is essentially a duplicate of "[Integer-distance sets](https://mathoverflow.net/q/136925/6094)." Apologies.

  [1]: https://i.sstatic.net/nDfBR.png