Preflop fundamentals: position, opening ranges and the first re-raise

Preflop is the cheapest place to fix mistakes and the place where most players make them. Every decision after the flop gets easier when the hand you arrive with makes sense, and no amount of postflop skill rescues a range that was wrong before the flop.

This guide gives you the reasoning rather than a chart to memorise. Charts are snapshots of one set of conditions — stack depth, position, who is still to act — and they stop being true the moment those change. The reasoning travels with you.

Why position is worth money

Position is two advantages stacked on top of each other: information and initiative. Acting last means you see what everyone does before you commit chips, and it means you can take a free card when you want one and charge for it when you do not. That is why the same hand can be a raise on the button and a fold under the gun.

The seats, in the order they act before the flop in a six-max game:

• UTG (under the gun) — first to act, worst position, tightest range.
• HJ (hijack) — one seat later; you can open slightly wider.
• CO (cutoff) — the seat before the button; this is where ranges get properly wide.
• BTN (button) — acts last on every street after the flop; widest opening range at the table.
• SB (small blind) — has already paid, but plays the whole hand out of position. Posted money does not make a hand playable.
• BB (big blind) — closes the action preflop, then acts first on every later street.

In a nine-max game the same logic stretches further: UTG+1 and two middle positions sit between UTG and the hijack, and each of them is a little wider than the one before.

Opening: size, and how the range widens

A standard open is 2 to 2.5 big blinds. Raising bigger feels safer and is not: a smaller size lets you open more hands profitably, and it loses less when someone re-raises you. You are buying the blinds and the initiative, not trying to build a big pot with a hand you do not know is good yet.

What makes a hand worth opening, in order of importance:

• Playability — suitedness and connectedness. A hand that can make straights and flushes has more ways to win than its high-card strength suggests.
• Nut potential — a hand that makes the second-best flush is not the same asset as one that makes the best one.
• Raw strength — pairs and big aces; these carry the top of every range.
• How many players are left to act — the fewer behind you, the less often someone wakes up with a hand.

Put together: under the gun you open a tight, strong range; by the cutoff and button you are opening hands that mainly win by taking the blinds and by playing well in position afterwards. That is the whole shape of a preflop chart, and it is more useful than the chart.

Facing a raise: the 3-bet

A 3-bet is a re-raise — the second raise in the hand. It does two different jobs, and good players do both:

• For value — with hands that want more money in the pot while they are ahead, and that suffer less from being called because they have equity when behind.
• As a bluff with blockers — with hands that are too weak to call but that hold cards your opponent needs. An ace or a king in your hand means fewer combinations of the big hands they can have, which makes their fold more likely.

A useful default is three times the open, plus one more multiple for each caller in between. The deeper you are and the better your opponent, the more you want your 3-betting range to be polarised — very strong hands and chosen bluffs, with the medium hands flat-calling instead.

Facing a 3-bet

Three options, and one habit to avoid:

• 4-bet with the top of your range, plus a small number of blocker bluffs so that your 4-bets are not only aces and kings.
• Call with hands that play well in a raised pot and can stand the pressure — pairs, suited broadways, suited aces.
• Fold everything that would need to improve just to become a marginal call. This is most of your opening range, and folding it is not weak; it is the range working as designed.

The habit to avoid is cold-calling a 3-bet out of position. You will be guessing on every street with a hand whose value you do not know, and your opponent knows exactly what you have because of how you got there. If you are not comfortable playing it after the flop, folding preflop is the cheaper mistake. Working out how often you have to defend is arithmetic, and it is covered in pot odds, equity and EV.

Five preflop leaks that cost the most

1. Limping instead of raising. You put money in without buying the blinds or the initiative, and you invite the whole table in behind you.
2. Defending too wide out of position. A hand that is a comfortable call on the button is often a fold in the blinds: you will play the rest of the hand first to act with a weak range.
3. Ignoring position entirely. The same two cards are worth different amounts in different seats. If your opening range is identical from every position, it is too tight in late seats and far too loose in early ones.
4. C-betting every flop. Betting because it is your turn is how you turn a good preflop range into a bad postflop one; some flops favour the caller's range, and those are the ones to check.
5. Slow-playing big hands preflop. The pot is small now and your opponents are more willing to put money in now than on a scary board later. Build it while they are still interested.

How to practise this in the trainer

Open the training table and play hands while limiting what you pay attention to. The panel grades your preflop decisions like any other, so a session where you only look at the open and the response to a raise is a session you can actually finish learning something from.

Two concrete drills: play a stretch where you only open from the cutoff and button, and watch whether the grades confirm that your range there is right; then play a stretch where you fold everything marginal to a 3-bet out of position, and see what that does to your EV loss. Both are cheap to test because preflop pots are small — which is exactly why it is worth fixing them first. The reasoning behind the frequencies is in what GTO actually means, and the mechanics of using the panels are in how to use this trainer.