How to play
- 1. Roll the lineFive stations in a row. Each round, every station rolls a die and passes at most that many units downstream.
- 2. Feel the trapAverage roll is 3.5 - so the line “should” ship 3.5/round. It won’t. Watch the gap grow.
- 3. Break it harderGive station 3 a smaller die (d4): now there is a true bottleneck. Watch WIP pile up in front of it.
- 4. Fix it with DBRDrum-Buffer-Rope releases new material at the bottleneck’s pace. Same throughput, a fraction of the WIP.
The dice line
Play
Scenario
Push: station 1 pulls fresh raw material every round, as much as its die allows.
Score
Cumulative shipped (red) vs the 3.5/round myth (grey dash) vs bottleneck pace (navy dash).
Total WIP by round - push feeds the monster; DBR starves it politely.
Try these experiments
- Balanced line, push, 20 rounds: everyone averages 3.5 yet the line ships ~2.8/round. Dependency + variability quietly taxes ~20%.
- Switch to S3 = d4. The whole line now ships at station 3’s pace (~2.5) while WIP in front of it explodes - an hour lost at the bottleneck is an hour lost forever.
- Same bottleneck, DBR mode: throughput identical, WIP clearly lower. You didn’t speed anything up - you just stopped releasing work the constraint can’t eat.
About this game
The concept
Goldratt’s dice game (The Goal): in a dependent line, statistical fluctuations don’t average out - they accumulate as WIP and lost throughput. Balancing capacity everywhere is the trap.
How it works
Each station moves min(die, upstream buffer) per round. DBR ropes raw-material release to the drum (the constraint’s roll) plus a small protective buffer in front of it.
Winning strategy
The five focusing steps: identify the constraint, exploit it, subordinate everything else, elevate it, repeat. Only the bottleneck’s dice matter - polish those.