Step-by-step: one evenin wid D’Alembert
One unit up afta a loss, one unit down afta a win, red evry spin fi a hundred spin. Di softes system, an wah soft cost.

A simulate D’Alembert session a 100 spin, $5 a unit. Di stake drop back to $5 five time, drif up to $80 inna a bad patch, an finish at $55 wid di session down $40. Di system weh feel like balance an nuh balance.
Walk tru di system
A loss move one step up. A win move one step back.
Stake an result deh inna unit a di base bet.
Di plan
Start wid one unitmoney mattaUnitDi base stake weh a system or a playa work wid. Dem describe progression inna unit suh dem work at any table.Read di whole ting →, $5, pon redbet demRedEven-money bet pon di 18 red numba. Inna French: rouge.Read di whole ting →. Afta a loss, add a unit; afta a win, tek one off, but neva go below one. Di theory, weh d’Alembert neva put forward but im get di blame fi it, a dat win an loss balance out, suh fi evry pair a one loss an one win wi up a unit. Di arithmetic seh red win 48.65% a di spin dem, suh loss beat win by bout one inna forty, an di stake drif up ova time.
Spin 1–30
Fourteen red, fifteen blackbet demBlackEven-money bet pon di 18 black numba. Inna French: noir.Read di whole ting →, one zeropon di wheelZeroDi one green pocket weh no even-money, dozen or column bet nuh cover; a weh di house edge come fram. Nex name: single zero, 0.Read di whole ting →. Di stake climb to $20 inna a run a tree loss, come back to $5 by spin 18, an go up to $25 by di end a di stretch. Net +$20. Evry loss-win pair net a unit jus like dem seh; di extra loss dem nyam dem up. It feel like a slow pump weh mostly work.
Spin 31–65
Di bad patch. Thirteen red gainst twenty-two weh nuh red, an one a dem a run a seven loss. Fram $5 at spin 41 di stake climb one unit at a time to $80, an evry $75 loss wipe out fifteen a di $5 win dem fram bifo. Net −$485 fi di stretch; runnin −$465. Nutten big neva happen pon nuh one spin; a di drif do it.
- p10 −$500
- p25 −$500
- median −$500
- p75 −$500
- p90 +$885

Spin 66–100
Twenty red to fifteen weh nuh red, an di stake a come down fram $80 toward $55 inna $5 step. Evry win pon a high stake get back real money: a $75 win afta a $70 loss a di pair a net +$5, but di pair big. Net +$425 fi di stretch; final −$40.
Di account
Average stake bout $37, suh total bet bout $3,670 gainst $500 fi a flat $5 bettor. Expected lossmathsExpected lossExpected value times all di money yuh bet; di average amount yuh lose ova a session or a period (di loss yuh fi expec pon average).Read di whole ting → pon $3,670 a $99; actual −$40, unda one standard deviationmathsStandard deviationDi square root a variance; ow far a result usually deh fram di expected value.Read di whole ting →. Di drif inna di stake size a di whole effect a di system: more money pon di table, di same 2.70% off a evry dolla, an a wider distribution a result.
Wah di session show
D’Alembert a di gambla fallacy write as a stakin rule: it tek fi granted seh win an loss wi even out soon enough fi di stake come back down. Dem even out inna di long run by dilution, nuh by correction, an di stake nuh have nuh reason fi go back to one unit. It a slow system widout nuh cliff, an di slowness a why playa believe inna it.
Question dem
Hardly. Di stake grow by one unit fi evry loss, it nuh double, suh it tek a very long bad run fi reach di limit.
Yes, an di cap turn it inna flat bettinstrategy demFlat bettinFi bet di same amount evry spin. Di baseline weh dem compare evry progression gainst.Read di whole ting → at di cap afta a bad run. Any cap good; none a dem change di edge.
Inna 1754 im argue seh tail more likely afta a run a head. Gambla weh agree wid im name di system afta im. Im woulda shame.
Sumting fi laugh

Di softes system. It drif instead a drop off a cliff.
Source dem
- d’Alembert, J. “Croix ou pile.”
- Ethier, S. N. The Doctrine of Chances: Probabilistic Aspects of Gambling.