They have been used in playground duels for decades.
But enthusiasts looking forward to smashing their rival’s conker should be braced for disappointment – because the heatwave has left this year’s batch too small and weak for fighting.
The depleted size has panicked organisers of the World Conker Championships, held in the UK, who have drawn up plans to import conkers from Germany so the event can go ahead.
It would be the first time in more than 40 years that the event, which started in 1965, has had to use horse chestnuts from overseas.
If the World Conker Championships organisers are forced to import the nuts it would be the first time in more than 40 years that the event has had to use horse chestnuts from overseas
Organiser St John Burkett said a number of measures, including freezing conkers, are being discussed before the tournament in Southwick, Northamptonshire, next month.
He said: ‘The conkers are not the same size or quality this year, which is giving us a number of problems and we do not know whether they can give us a good game.
They were very slow to get started during the spring and they haven’t really developed as they might since.’
The competition’s 256 adult competitors rely on the collection of approximately 3,000 conkers for the event to go ahead.
If not enough appropriately sized conkers are collected in the days before the competition, players travelling from abroad will be asked to bring supplies.
Mr Burkett added: ‘There are decent conkers in Germany and we have competitors coming from there who can bring them in under EU rules.
‘We might appeal to competitors coming to bring them with them. One way or another we can get hold of conkers that are big enough.’
Meanwhile, experts say that the heat coupled with a drought over the summer have caused UK horse chestnuts to shrivel.
Martha Boalch, from conservation charity the Woodland Trust, said: ‘This year’s heatwave will have encouraged fruit to grow more rapidly, but lack of water may have stopped conkers from growing to their full potential.
‘Although we’ve only had a small number of conkers recorded so far, we are seeing more ripe conkers coming through, so all is not lost for our favourite sign of autumn.’