Part: Part Nine - Inflection Points: M, Q & the Zones

Effective M at a short table

Pre-flop
Blinds 400 / 800 (100 ante)Pot 1,700 (2.1 BB)Raw M 8 • Effective M 4 (5-handed)COJ♥10♣● 13,600 (17 BB)YOUraw M 8, but 5-handedSB● 16,800 (21 BB)posts 400 (0.5 BB)BB● 16,800 (21 BB)posts 800 (1 BB)D

You have 13,600 and an orbit costs 1,700 (400 + 800 + five 100 antes), so your raw M is 8. But the table is now 5-handed - the blinds come around far faster.

Raw M 8 (Orange), but five-handed. How does that change your play?

WhyThe blinds come around every five hands now instead of every ten, so each orbit your M counts buys half as many hands. Effective M is 8 × 5 / 10 = 4: Red, not Orange. Play the ranges that shorter reality demands: open wider and jam sooner rather than waiting for the raw number to catch up.
What happensYou recalibrate to the faster clock and widen accordingly - the raw 8 was quietly lying to you about how much time you had.
Raw M assumes a full table; short-handed it overstates your comfort because the blinds reach you more often. Convert to Effective M and get aggressive earlier than the raw figure suggests.

Correct raw M for table size: short-handed you post the blinds far more often, so the same stack is effectively shorter - loosen and attack sooner.