probe

A probe is a turn lead by the preflop caller after the raiser checks the flop. It's distinct from a donk-bet: a donk is a successive OOP lead, while a probe follows the opponent's check.

Detailed Explanation

A probe's +EV source is the weakness exposed by the opponent's check:

• After the raiser checks the flop, the strong-hand density in their range drops
• Weak and medium-strength hands struggle on the turn against a probe
• Probe exploits the opponent's "checking back to see a free turn" weak range

Probe range design:

• Value: top pair+, strong made hands (the opponent's check already pruned their strong range)
• Semi-bluff: hands that gain new draws on the turn (e.g. flop K72r, turn 5h, with 4h3h flush draw + gutshot)
• Pure bluff: selected hands with blocker effect

Probe sizing is typically 50-66% pot — large enough to fold out the opponent's middle strength, but not so large that only nuts call.

Common Use Cases

• BB defending BTN open: BTN checks back the flop, BB probes the turn at high frequency
• Caller benefits from a key turn card: turn brings a card that strengthens the caller's range (e.g. broadway turn on a low-connected flop)
• Opponent's cbet frequency is high but fold-to-probe is also high: identify the leak and increase probe frequency
• Multi-way pots: after one player checks, the next player's probe is the new "initiative handoff"