Step 1: The Conker
The conker got its name from the game, rather than the other way round - before the horse-chestnut was introduced to Britain, the game was played with acorns or snail-shells (the word conker actually means "hard", and comes from the same root as the French conque, meaning "conch (shell)").
Step 2: Preparation.
Being a playground game, the drilling has been done with many tools, typically screwdrivers and found nails, and the string is often a shoelace.
The neater and rounder the hole, though, the less likely the conker is to split. Use of a power drill is therefore recommended, as seen below, with #2 son helping me prepare for a Cub Pack contest.
The drill-bit used should match the string being used - thread the conker onto about 30-45cm (a foot to 18 inches) of string, then tie a good fat knot in the end of the string to stop the conker slipping off.
Shoelaces have an advantage, with a built-in threader (the aglet); you may have to resort to a large needle, awl or bent paperclip to thread the string through.
Step 3: Play
Decide who goes first any way you like - toss a coin, scissors-paper-rock, pistols at dawn - and then one player wraps the loose end of the string around one finger, and holds their conker out at arm's length.
They must hold it still, without swinging or swaying, and without flinching when their opponent takes a swing.
The other player then holds the string of their conker in one hand, briefly restrains the conker in the other, and swings as hard as he can to strike the hanging conker.
If the conker is struck, the conker-swinging player gets another go.
If the conker is missed, the players swap over - the hanging-conker-player becomes the conker-swinging-player, and vice versa.
This continues until one conker breaks or comes off the string.
Step 4: The Finer Points
If the swinging conker just brushes the hanging conker, the attacking player must shout tips before the defending player shouts miss.
If there is a dispute about who shouted first, the bystanders must decide. If there are no bystanders, it is usually sorted by a lot of shouting, stamping and the occasional fist.
If the two conker-strings tangle, the first player to shout strings gets the next swing.
It is possible for a conker to come off its string, otherwise unharmed, and fall to the floor. The attacking player shouts stampsies, and attempts to flatten the conker underfoot before the defender can rescue it. This rule has caused countless barked and bent fingers over the years...
Occasionally, a player may lose their grip of the end of the string, and the conker, with string, will go sailing across the playground, potentially quite some way. If this happens, somebody, somewhere, will shout scramble, and everybody will try and grab the conker. Whoever gets it first will win ownership of the conker, but not the string (especially if it is a shoelace - the lace owner needs it to walk home).
Step 5: Scoring.
The other conker then gains a point. That's the conker gains a point, not the conker's user.
When a conker breaks its first opponent, it becomes a one-er or a once-er. When it breaks a second conker, it becomes a twicer or two-er. Three wins makes it a three-er, then four-er, fiver and the traditionally-significant sixer.
Scores are cumulative as well - if a twicer bets a sixer, it becomes a niner (it's own two, plus the other conker's six, plus one for this win). It is thus possible for a relatively few matches to turn a reasonably successful conker into the near-mythological ninety-niner.
Because the points are retained by the conker, not its user, successful conkers can become valuable commodities in the traditional playground, trading for sweets, comics and favours.
Step 6: Cheating.
Officially, anybody caught cheating is frowned upon, even shunned, but a successful cheat is almost as lauded as a successful player.
Cheats include; using last year's conker (a laggie), brief baking, time on a hot radiator, pickling, soaking and drying and coating with varnish (fresh conkers are shiny, and kept so by constant polishing in small boys' pockets during lessons).
In my day, rumours abounded of conkers made utterly indestructable by injecting some sort of glue into the conker, to fill the space between skin and flesh with a stone-hard inner armour. No such conker was ever found, but the rumours returned every year.
Fears of cheating have meant that official championships usually ban players from bringing their own conkers, which upsets traditionalists.
Step 7: Sustainability
On top of that, around half the UK's horse chestnut population is suffering from parasitic and bacterial infections like leaf-miners and "bleeding canker".
So, to play conkers with a clear conscience, don't take all the conkers you see on the ground. Instead, kick a few away from the tree, out of its shade, and gently step on them to press them into the ground, then kick some leaf-litter over them.
You could even take a few and propagate them at home - plant them in pots, in a normal (peat-free) potting compost, and leave them out in the garden to germinate. You could bring them on in a greenhouse, or under a cloche, but make sure you don't let them dry out. From the BBC...
Paul Bray asks...What's the best way to grow a conker tree and an acorn tree, from a conker and an acorn, how long will it take and will they last? Thanks.
I find the best method Paul is to plant your conker and acorn seeds in a peat and sharp grit sand mixture - in pots or a two inch sheet tray. Cover the seeds with approximately one quarter to half an inch of peat and grit mixture. The pots/seed trays can placed outside in the garden but you will need to cover them with a fine plastic mesh to keep mice at bay. The time of year to plant your seeds is during the autumn when you have collected the seeds and they will start to germinate early spring time when they can be repeated into single pots.
When the seedlings seem tough enough, take them back where they came from, and plant them away from careless feet and out of deep shade, so that, in fifty or a hundred years, your descendants can continue to play conkers.