Our human interface with reality

The Knife Game (Five Finger Fillet)

Many skills once learned can be performed significantly faster without visual monitoring.
One excellent example to compare with Fitts’ stylus tapping experiments, is the Knife Game (also called the Five Finger Fillet).

Note the remarkable speed at which this complex sequence of movements is performed, after training!

From YouTube Video

  • The duration of each movement is largely independent of the distance traversed.
  • Speed little influenced by increased accuracy required for larger displacements.
  • Average stab rate = 5.5/second.

In contrast, with visual monitoring the duration is proportional to the required accuracy, hence is longer for larger displacements.

Knife Game – Sequence of Movements



In the Knife Game (Five Finger Fillet), the point of the knife is rapidly moved between a sequence of positions between and outside the fingers. Note that the larger displacements (5,6) demand much greater accuracy than the shortest one (1).



  • The task can be completed totally blindfold

The Knife Game performed blindfold. No visual feedback possible.

A learned skill using dead-reckoning.

From Rusty Cage’s YouTube Video