An independent reimplementation of pétanque, the Provençal boules game.
The form played today was codified at La Ciotat in 1907, and the sport is governed by
the Fédération Internationale de Pétanque et Jeu Provençal
— the FIPJP, founded in 1958. Every rule below is taken from the FIPJP’s
Official Rules for the Sport of Pétanque, the edition approved by its Executive
Committee in December 2020, together with the FIPJP’s Homologation of
Competition Boules (January 2023) and its Precision Shooting Rules.
What is faithful
The boule: metal, 70.5 to 80 mm across and 650 to 800 g, and it must
be hollow with no lead or sand in it. Those three facts together fix its moment of
inertia at between 0.53 and 0.60 of m a² — not the textbook sphere’s
0.4 — and that is what decides how far it runs. Steel hardness 35 to 55 HRC,
and re-tempering to change it is forbidden, so the hardness you buy is the hardness you
keep. Art. 2; Homologation Art. 3a
The jack: 30 mm ± 1 mm and 10 to 18 g, wood or an approved
synthetic, never magnetic. Art. 3
The terrain: 15 × 4 m for championship play, and never below
12 × 3 m. Barriers a metre outside the line.
Art. 5
The circle: 50 cm inside diameter for a manufactured one, 35 to 50 cm for a drawn
one; both feet entirely inside it and on the ground until the boule has landed.
Art. 6
Throwing the jack: 6 to 10 m from the circle’s internal edge, at
least 50 cm from any obstacle and from the end line — and expressly no minimum
from the side lines. One attempt only: if it is invalid the opponent
places the jack, and the team that lost it plays the first boule. (Three
alternating attempts was the rule before 2016 and is still all over the internet.)
Art. 6, Art. 7
The following end is thrown from a circle traced around where the jack finished —
and when that leaves no room for the full 10 m throw in any direction, the thrower
steps back in line with the previous end’s play. On a 15 m lane that happens
about 45% of the time. Art. 7
The ring scribed round the jack is Art. 6, not a heads-up display:
“the players must mark the position of the jack initially and after each time it is
moved. No claims will be allowed for an unmarked jack.”
Art. 6
Dead boules and jacks: only after completely crossing the boundary, so a
boule straddling the line is still valid. Viewed from above the boule is a disc and the
terrain a rectangle, and the test is written that way — which matters at the corners.
Art. 19, Art. 9
The jack is also dead beyond 20 m or nearer than 3 m from the circle.
Art. 9 (3)
Whose turn: after the first boule, the team that does not hold the point
plays — except when the two nearest boules of opposing teams measure equal, when the
team that played last plays again. Art. 16,
Art. 29 (3)
A dead jack scores nothing if both teams still hold boules, and otherwise gives
the team still holding them one point for every boule remaining to be played.
Art. 14
An equidistant pair with no boules left kills the end; so does an end that finishes
with nothing inside the terrain. Art. 29
Formats: triples with two boules each, doubles and singles with three — six boules a
team either way, which is why an end in singles can score at most 3 and in triples 6.
Art. 1
Games to 13, or 11 for leagues and qualifying heats.
Art. 5
Tir de précision, the FIPJP’s own shooting discipline, at its real
geometry: a 1 m target circle, throwing circles at 6, 7, 8 and 9 m, and the scoring ladder
that is the only place in any FIPJP document where a carreau is given a
rule — five points when the target leaves the circle and your boule stays in it. The engine
implements and scores it, and labels your own tirs by it; it is not yet a separate playable
mode.
Precision Shooting §1, §3, §4
One rule the rulebook does not contain
The single most important rule in the sport — that the team holding the point scores
one for every boule closer than the opponent’s best — is never stated in its
own right in the December 2020 edition. It appears only inside
Art. 29 (2), as the resolution of the equidistant case, and inside
Art. 14 (2) for a dead jack. Art. 16 uses “hold the point” without
ever defining it, and Art. 5 gives the target of 13 without saying how a point is won.
This app reconstructs it from Art. 29 (2) and says so. Nor does anything in the
rules say what a tape measures: this app measures the gap between the surfaces,
which is what a tape between a boule and the jack actually reads — and because
Art. 2 lets each player choose a diameter, that is a different ordering from
centre to centre.
The ground, which no rule describes
Art. 5 says only that pétanque “is played on any surface”, and there
is no published measurement of a boule’s restitution or of a steel sphere’s
rolling resistance on gravel. So the terrain here is built from first principles and
labelled. A landing boule presses on the gravel with the bearing pressure over the
horizontal projection of its buried cap, ploughs forward against the same pressure over the
cap’s vertical projection, and digs a hole whose floor it then has to climb out of. That
one law gives all three shots without a special case: a portée arriving at
50–70° digs 20 mm in and stops within a few centimetres, a
demi-portée at 30–40° runs two to four metres, and a roulette
arriving flat runs the length of the terrain. The shape of the law is
Katsuragi & Durian’s measured granular-impact force law; its level is
calibrated, and the specification panel says which numbers were calibrated against what.
The only thing the rules say about the ground is Art. 10, which lets a player
“fill in a hole which would have been made by one boule played previously” —
so the holes are drawn.
The carreau is not scripted
A head-on impulse between equal masses leaves the shooter (1 − e)/2 of
its speed, which goes to zero as the restitution goes to one. That is the carreau, in one line
of algebra, and there is no carreau anywhere in this engine’s collision
solver, terrain model or scorer. The restitution itself is derived: the FIPJP’s
own 35–55 HRC hardness band gives a yield stress, and Johnson’s elastoplastic
impact analysis turns that into e = 0.57 at the legal soft floor and 0.80 at
the hard end, at shooting speed. So a harder boule carreaus better — measurably,
and this is a correction to the usual advice, which holds that shooters should buy
soft boules because a low restitution keeps them in the vacated place. It does the opposite.
What a soft boule really is better at is a mis-hit: a smaller normal impulse deflects it
less, so an off-centre strike carries on towards the jack instead of being flung aside.
What is this app’s own
The three shots as release heights and launch angles, and the donnée and
backspin as controls. Backspin is not decoration: a sphere reaches rolling at
(v₀ − k r ω₀)/(1 + k), so
it subtracts directly from the roll-out — and it is what turns a hit into a carreau.
The backspin needed rises with the distance.
The range table, the power meter, the aim wobble, and the opponent — four levels
that differ only in the spread on their aim, donnée and spin. Nothing about the
opponent is scripted: it throws through the same function you do.
Every colour, the cameras, and the coloured cap on each boule. Real sets are told apart by
their striations, which Homologation Art. 6 allows up to 1 mm deep and which are
drawn too.
The donnée marker on the terrain, which Art. 16 would forbid in play —
“the player must not use any object or draw a line on the ground to guide them”.
It is an aid.
What it does not do
No umpire, no cards, no time limits — Art. 21’s one minute a boule and
the whole of Art. 32 to Art. 41 are out.
No obstacles on the terrain, so Art. 9 (2)’s invisible jack and
Art. 9 (4)’s crossed lanes cannot arise. One lane, so all four of its lines
are dead ball lines.
Nobody stops a boule, so Art. 15 and Art. 20 do not arise, and nobody disturbs
a boule while measuring, so Art. 28 does not either.
Not affiliated with, endorsed by or connected to the FIPJP or any of its member
federations. CREDITS.txt lists every source by article and every
calibrated and reconstructed figure.