<h1>Part0 - Inspired by these:</h1>
<ol>
<li><p>Poker can be simplified to <a href="https://en.wikipedia.org/wiki/Kuhn_poker" rel="nofollow noreferrer">Kuhn poker</a>.</p>
</li>
<li><p>The Monty Hall problem is easy to understand if instead of 3 doors, you have 100 doors and then Monty opens all but 1.</p>
</li>
</ol>
<h1>Part 1</h1>
<p>I think of a simplified version of sevens where there are only 12 cards: fives, sixes and sevens.</p>
<ul>
<li><p>Assume also: 1 pass per player, 4 players, no jokers, all the sevens removed before cards are dealt and you 1st.</p>
</li>
<li><p>Suppose each player gets 1 five and 1 six of the same suit.</p>
</li>
</ul>
<p>Now it's unnecessary to pass because if you play your six, then you're not helping the others' finish their hands.</p>
<p>Case 1: Suppose you pass. Then the other 3 players play their six. Then you have to play your six. Then they all play their five. Finally, you lose.</p>
<p>Case 2: Suppose you play your six. No matter what the others do, you'll win.</p>
<h1>Part 2</h1>
<p>I'm not really bothered to continue generalising until we reach the whole deck and add 2 more passes. I think I get the idea:</p>
<p>2A. Conjecture, which if true might be the 'fundamental theorem of sevens' similar to the <a href="https://en.wikipedia.org/wiki/Fundamental_theorem_of_poker" rel="nofollow noreferrer">fundamental theorem of poker</a>:</p>
<blockquote>
<p>If you have a safe card but pass instead of playing, then you just waste time to clear your hand.</p>
</blockquote>
<p>2B. I believe the contrapositive is:</p>
<blockquote>
<p>A pass means the player has no safe cards or is making their own situation worse.</p>
</blockquote>
<p>Ah well maybe I'm wrong, but I don't think there's any <a href="https://en.wikipedia.org/wiki/Slow_play" rel="nofollow noreferrer">slow playing kinda trick</a> here: like you pass even though you have safe cards and then this somehow tricks your opponent</p>
<h1>Part 3:</h1>
<p>Conclusion: When do you pass?</p>
<p>You pass either because you're forced to or because you're trying to not play a non-safe card... I guess.</p>

CC BY-SA 4.0
2022-09-22T11:41:13.987Z
2024-04-09T13:52:36.263Z
2024-04-09T13:52:36.263Z
BCLC
<p>In the game of Sevens, also known as Fan Tan/Card Dominoes/<a href="https://boardgames.stackexchange.com/questions/57425/is-there-a-2-player-variation-of-any-of-sevens-fan-tan-domino">Shichi Narabe (7並べ)</a>, whenever there are options to pass, <strong>why wouldn't I just use up all my passes at the start regardless of what my opponents do?</strong></p>
<p>Please give an example of a hand in 4-player Sevens where all the cards are dealt and there's no joker and all the sevens are played after the cards are dealt.</p>
<p><strong>Context</strong>: I am trying to see how Sevens <strong>isn't just pure luck.</strong></p>
<ol>
<li><p>Case 1: I understand if there are no passes, then it's indeed a pure luck game.</p>
</li>
<li><p>Case 2: If there are no passes and if it's optimal to use all my passes at the start, then we just get Case 1.</p>
</li>
</ol>
<p>Or please just tell me where I can read about this. My google-fu is currently failing me.</p>

<sevens><shedding>
How isn't Sevens pure luck?
BCLC
# How isn't Sevens pure luck?

(Asked by: username_0 on 2022-09-12)

In the game of Sevens, also known as Fan Tan/Card Dominoes/[Shichi Narabe (7並べ)](https://boardgames.stackexchange.com/questions/57425/is-there-a-2-player-variation-of-any-of-sevens-fan-tan-domino), whenever there are options to pass, **why wouldn't I just use up all my passes at the start regardless of what my opponents do?**

Please give an example of a hand in 4-player Sevens where all the cards are dealt and there's no joker and all the sevens are played after the cards are dealt.

**Context**: I am trying to see how Sevens **isn't just pure luck.**

1. Case 1: I understand if there are no passes, then it's indeed a pure luck game.
2. Case 2: If there are no passes and if it's optimal to use all my passes at the start, then we just get Case 1.

Or please just tell me where I can read about this. My google-fu is currently failing me.

**Tags:** sevens, shedding


---

## 1 answers

### Answer by username_0 on 2022-09-22. Score: -1

# Part0 - Inspired by these:

1. Poker can be simplified to [Kuhn poker](https://en.wikipedia.org/wiki/Kuhn_poker).
2. The Monty Hall problem is easy to understand if instead of 3 doors, you have 100 doors and then Monty opens all but 1.

# Part 1

I think of a simplified version of sevens where there are only 12 cards: fives, sixes and sevens.

* Assume also: 1 pass per player, 4 players, no jokers, all the sevens removed before cards are dealt and you 1st.
* Suppose each player gets 1 five and 1 six of the same suit.

Now it's unnecessary to pass because if you play your six, then you're not helping the others' finish their hands.

Case 1: Suppose you pass. Then the other 3 players play their six. Then you have to play your six. Then they all play their five. Finally, you lose.

Case 2: Suppose you play your six. No matter what the others do, you'll win.

# Part 2

I'm not really bothered to continue generalising until we reach the whole deck and add 2 more passes. I think I get the idea:

2A. Conjecture, which if true might be the 'fundamental theorem of sevens' similar to the [fundamental theorem of poker](https://en.wikipedia.org/wiki/Fundamental_theorem_of_poker):

> If you have a safe card but pass instead of playing, then you just waste time to clear your hand.

2B. I believe the contrapositive is:

> A pass means the player has no safe cards or is making their own situation worse.

Ah well maybe I'm wrong, but I don't think there's any [slow playing kinda trick](https://en.wikipedia.org/wiki/Slow_play) here: like you pass even though you have safe cards and then this somehow tricks your opponent

# Part 3:

Conclusion: When do you pass?

You pass either because you're forced to or because you're trying to not play a non-safe card... I guess.


---

