J2s: the 4 combos
A suited hand needs both cards in one suit, so each of the 4 suits gives exactly 1 combo: 4 in all.
Below are the 4 exact two-card holdings in J2s. When a range chart marks J2s, it marks all of them together.
How cards you can see change the count
How many J2s combos can an opponent still hold? It depends on the cards you can see, and the table gives the answer for one card of each rank.
| Known card | J2s combos left |
|---|---|
| Ace | 4 |
| King | 4 |
| Queen | 4 |
| Jack | 3 |
| Ten | 4 |
| Nine | 4 |
| Eight | 4 |
| Seven | 4 |
| Six | 4 |
| Five | 4 |
| Four | 4 |
| Three | 4 |
| Two | 3 |
Holding a jack or a two takes J2s from 4 combos down to 3, a cut of 25%. Any card of a different rank leaves all 4 combos in play.
When the board is paired
Board pairs take away more combos than a single card does. The table lists the J2s count for each possible pair on the board.
| Board pair | J2s combos left |
|---|---|
| Aces | 4 |
| Kings | 4 |
| Queens | 4 |
| Jacks | 2 |
| Tens | 4 |
| Nines | 4 |
| Eights | 4 |
| Sevens | 4 |
| Sixes | 4 |
| Fives | 4 |
| Fours | 4 |
| Threes | 4 |
| Twos | 2 |
Jacks or twos paired on the board leave 2 combos of J2s, and no other pair changes the count of 4.
A worked example
Here is the count in a real spot. You hold a jack and a three, which leaves 1,225 hands for your opponent. J2s is 3 of them, a 0.24% chance. A hand with no jack in it would give 4 combos, 0.33%.
How strong is J2s?
Number 104 of 169: that is where J2s sits when hands are ordered by equity against a random hand, below the middle of the ranking. The figure is 47.38%, wins plus half the ties.
Counting from the top, J2s is where the running total reaches 770 combos (58.07% of 1,326). The 766 combos before it are all stronger classes.
J2s against ranges of hands
Equity against a range is a weighted average of the matchups with every hand in it. The numbers for J2s: 25.32% against the top 5 percent (60 combos), 30.08% against the top 10 percent (130 combos), 32.92% against the top 20 percent (264 combos), 34.43% against the top 30 percent (386 combos) and 36.35% against the top 50 percent (658 combos).
| Opponent range | Combos in range | J2s equity |
|---|---|---|
| Top 5 percent | 60 | 25.32% |
| Top 10 percent | 130 | 30.08% |
| Top 20 percent | 264 | 32.92% |
| Top 30 percent | 386 | 34.43% |
| Top 50 percent | 658 | 36.35% |
J2s is behind all five of these ranges, even the top 50 percent, so it is the underdog on average against each of them.
How much of the top 10 percent can an opponent still hold? Across the 4 combos of J2s you might hold, 122.00 of its 130 combos remain on average. That is 8.00 combos fewer than the 130 an opponent has before you look.
Hands next to J2s
The hands on either side of J2s in the ranking make a useful pair of comparisons. J2s has 56.36% equity against 96s, the hand ranked number 103: it wins 55.69% of boards, ties 1.33% and loses 42.97%. It is the favorite in that matchup. J2s has 29.42% equity against Q2o, the hand ranked number 105: it wins 27.51% of boards, ties 3.82% and loses 68.67%. It is the underdog in that matchup.
The offsuit form, J2o, ranks number 121 with 44.35% equity against a random hand. J2o is 3 times as many combos but 3.03 points weaker against a random hand.
Questions about J2s combos
- How many combos of J2s are there?
- 4 combos, which is 0.30% of the 1,326 two-card starting hands, so you are dealt J2s about 1 time in 331.5.
- How many J2s combos are left if I hold a jack?
- 3 combos of J2s remain out of 4. With a three as your other card, an opponent has it about 1 time in 408.
- Is J2s stronger than J2o?
- Yes, by 3.03 points: J2s has 47.38% equity against a random hand and ranks number 104, while J2o has 44.35% and ranks number 121. J2o has 12 combos to J2s's 4.
How this was computed
We counted from the deck itself: 1,326 possible two-card hands, each placed in one of 169 classes. A table row then deletes the combos that need a card known to be elsewhere, and the survivors are tallied.
Equity comes from an exact table of preflop matchups, every one of the 1,712,304 boards counted. A tie is half a win, and each hand in a range is weighted by the combos your cards leave.
Source: GeorgeLiPoker's own count of the 52-card deck and its preflop matchup table.