How to Play J4s Preflop (GTO)

How to Play J4s — Jack-Four suited Preflop Strategy

GTO opens J4s first-in from 1 of the 5 positions in 6-max cash — from the Small Blind onward. Earlier than that, it folds. In numbers: the button opens it 40% of the time and the lojack 0%; at 15bb it is a first-in shove from 1 of 7 seats.

6-Max Cash Opening (100bb)

How often GTO opens J4s first-in from each seat.

Button

40%

Small Blind

83%

Short-Stack Jam Frequency

How often J4s is a first-in shove at short stacks (tournament).

Stack	UTG	MP	LJ	HJ	CO	BTN	SB
5bb	0%	0%	0%	0%	0%	0%	96%
8bb	0%	0%	0%	0%	0%	0%	100%
10bb	0%	0%	0%	0%	0%	0%	100%
12bb	0%	0%	0%	0%	0%	0%	100%
15bb	0%	0%	0%	0%	0%	0%	97%
20bb	0%	0%	0%	0%	0%	0%	0%

Generated from our solver database · 6-max cash (NL500) & MTT Chip-EV · updated Sep 5, 2026 · method

J4s head-to-head

Exact preflop equity against the hands it usually runs into.

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The table above is J4s preflop at fixed stacks. Drill it with every other hand until the right open is automatic, or put J4s on a board of your choosing and solve the postflop with your own sizes.

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Playing J4s preflop

Playable in late position — open from the Small Blind onward and fold it from earlier seats. At 5bb it comes into the jamming range from 1 of the 7 seats — short stacks widen what's playable.

Position matters: from under-the-gun (LoJack) J4s opens 0% of the time, rising to 40% on the Button as fewer players are left to act behind you. The later you are, the wider you can open.

The common mistake with J4s is opening it from early position where the solver folds it. Respect the position threshold — it's an open from the Small Blind onward, not before.

How to Play J4s — Jack-Four suited Preflop Strategy

Playing J4s preflop

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