3x3 Speedcubing: The Ultimate Limits Forecast
History · Methods · Hardware · Math · Biomech · Top Cubers · Training · Statistics — toward a single & average forecast.
Metrics: HTM vs STM vs QTM vs ATM
Different metrics count different things:
| Metric | R | R' | R2 | M | R + L | Meaning |
|---|---|---|---|---|---|---|
| HTM | 1 | 1 | 1 | 2 | 2 | face turn = 1; academic default |
| QTM | 1 | 1 | 2 | 4 | 2 | quarter-turn only |
| STM | 1 | 1 | 1 | 1 | 2 | slice = 1; natural human |
| ATM | 1 | 1 | 1 | 1 | 1 | axial; R+L = 1 |
STM is the natural cubing metric. M is a single thumb-ring fingertrick — HTM counting it as 2 face turns is wrong for biomech. All TPS / move counts use STM here. HTM for academic, QTM for group theory.
HTM→STM conversion. CFOP slice-rare so HTM ≈ STM. Roux relies on M-slice; HTM exceeds STM by 5-10%. Cross-method comparison must normalize to STM, or Roux's 48 STM shows as 53 HTM.
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