<p>Calling <em>ron</em> does not give you a <em>yaku</em>.  What it will do is increase the <em>fu</em> count of your hand, but only if the hand is closed.  However, winning from a <em>ron</em> on an open hand does not increase the point value at all; contrarily, you could instead claim a 2-<em>fu</em> bonus by winning on a <em>tsumo</em>.</p>

<p>Once your hand is opened, the only way to win is to have a <em>yaku</em> that does not rely on a closed hand.  Opening your hand before you have a guaranteed <em>yaku</em>, or a good chance of building one, is often a mistake; not only does keeping your hand closed increase the number of <em>yaku</em> you can potentially make (especially "easy" <em>yaku</em> such as <em>pinfu</em> and <em>tanyao</em>), but you also have the option of adding the needed <em>yaku</em> just by calling <em>riichi</em> on an otherwise worthless hand.</p>

<p>If you do decide to open your hand, some common open-hand <em>yaku</em> which can be built follow:</p>

<ul>
<li><strong>Yakuhai</strong>: A complete set (not pair) of dragons, seat wind, or table wind.</li>
<li><strong>Chanta</strong>: Every set contains either honor tiles, or at least one terminal (1 or 9) tile.</li>
<li><strong>Itsu</strong>: Three melds "123", "456", "789" of a single suit.</li>
<li><strong>Honitsu</strong>: All tiles, except for honor tiles, comprise a single suit.</li>
<li><strong>Toitoi</strong>: Every set is either three or four of a kind (i.e. no <em>chi</em> melds)</li>
</ul>

<p>Some rulesets also allow a <em>yaku</em> for an open <em>tanyao</em> (no honors or terminal tiles).  There are of course others, but I find these listed above are typically the easiest to make on an open hand, especially if you open early.</p>

<p>Even if you can't memorize all of the <em>yaku</em>-bearing hands yet, it's worth it to at least memorize these ones for when you choose to go the open-hand route.</p>

<hr>

<p>That said, given the (incomplete) description of your hand, your best bet would've been to wait for a third dragon so as to claim a <em>yakuhai yaku</em>, and hoping to complete a pair involving one of your two bamboo tiles (while tossing the other).  Calling <em>chi</em> on the bamboo actually harmed your hand, since you no longer had any reliable way to form any <em>yaku</em>.</p>

<p>Not knowing the makeup of your open melds, I don't know if calling <em>chi</em> on a <code>I Bamboo</code> (instead of a <code>IV Bamboo</code>) would've completed a <em>chanta</em> (or possibly an <em>itsu</em>) hand; even if it was possible, it would still be a risky wait as passing on the <code>IV Bamboo</code> (while waiting on the <code>I Bamboo</code>) would put you into <em>furiten</em>.</p>

CC BY-SA 3.0
2012-09-26T12:00:07.253Z
Thank you! I must have misinterpreted the rules and somehow I was sure, that with an open hand I can't call tsumo without apparent yakus, but I can win with a ron. You have clarified this to me perfectly - now I understand. Thanks!
Mateusz Papiernik
CC BY-SA 3.0
2012-09-26T14:54:00.663Z
It may sometimes be useful to open your hand as the wall shrinks, even if you won't meet the yaku limit, simply to ensure your hand is in tenpai. This nets you points on an exhaustive draw.

A partially open hand in temporary furiten (by passing on a completing tile) can call a meld that would be a duplicate to end the temporary furiten (instead of waiting for a turn to pass).

As well as that, some rule sets will provide yaku for "events" rather than hands - for example, winning on the last draw/discard of the round.
Samthere
CC BY-SA 3.0
2012-09-26T07:13:15.217Z
2012-09-26T07:33:38.473Z
2012-09-26T07:33:38.473Z
goldPseudo
<p>I found <a href="http://www.ofb.net/~whuang/ugcs/gp/mahjong/mahjong.html" rel="nofollow noreferrer">this page</a> that explicitly states the problem in the OP.</p>

<blockquote>
  <p>Essentially, certain properties of the hand give multipliers (yaku [役]). At least one multiplier is necessary for the hand to win.</p>
</blockquote>

<p>Multiplier, or "fan", is based on properties of the hand or how it was won (yaku). For instance, a fully concealed hand (menzenchin tsumohou [門前清模和]) gives 1 yaku, so the win condition is satisfied. In the example given in the OP, no multipliers apply. For a list of multiplier sources, see <a href="http://www.ofb.net/~whuang/ugcs/gp/mahjong/mahjong.html#multipliers" rel="nofollow noreferrer">here</a>.</p>

<p>Other common sources of yaku include:</p>

<ul>
<li>fanpai [翻牌] / yakuhai [役牌] - "Pon of honors" - A tri or a quad in any element / the round or position wind.</li>
<li>tanyaochuu [断幺] - "No Terminals" - A hand with no terminals/honors. (Sometimes required to be closed though - this depends on the actual rules in effect)</li>
</ul>

CC BY-SA 3.0
2010-11-10T15:51:27.637Z
2017-11-19T02:31:13.393Z
2017-11-19T02:31:13.393Z
mafu
<p>The OP may have confused Ron with Riichi.  If you declare Riichi (hand is in Tenpai - one tile from completion), then stealing the last tile with Ron satisfies a Yaku.   But it is the declaration of Riichi that is the Yaku in this situation, and not the final Ron call.</p>

CC BY-SA 4.0
2021-06-17T14:31:46.127Z
2021-06-17T14:31:46.127Z
PJW
<p>I have just started learning Japanese Mahjong and I am a bit lost as to why this hand failed.</p>

<p>I did several pons and chis over the course of a hand, having a total of three open melds (one set and two sequences).</p>

<p>Apart from these I had an incomplete bamboo sequence of II and III as well as a pair of dragons, therefore I was on a single wait for I or IV bamboo stick tile. When the IV tile appeared in one of the discards of other players, I was given a choice to do another chi and declare another open meld, but I couldn't win with a ron. Why was that?</p>

<p>Am I wrong that winning by ron guarantees a single needed yaku to win a hand, just like Closed Tsumo does?</p>

<p>After declaring the chi I was offered with, my hand was left with a single pair of tiles, one of which I had to discard.</p>

<p>Eventually the round finished with a draw.</p>

<p>Why couldn't I win this hand with a ron on the IV bamboo tile, and why was I given only the choice of chi instead?</p>

<riichi-mahjong>
Why couldn't this hand win with ron?
Mateusz Papiernik
# Why couldn't this hand win with ron?

(Asked by: username_0 on 2012-09-25)

I have just started learning Japanese Mahjong and I am a bit lost as to why this hand failed.

I did several pons and chis over the course of a hand, having a total of three open melds (one set and two sequences).

Apart from these I had an incomplete bamboo sequence of II and III as well as a pair of dragons, therefore I was on a single wait for I or IV bamboo stick tile. When the IV tile appeared in one of the discards of other players, I was given a choice to do another chi and declare another open meld, but I couldn't win with a ron. Why was that?

Am I wrong that winning by ron guarantees a single needed yaku to win a hand, just like Closed Tsumo does?

After declaring the chi I was offered with, my hand was left with a single pair of tiles, one of which I had to discard.

Eventually the round finished with a draw.

Why couldn't I win this hand with a ron on the IV bamboo tile, and why was I given only the choice of chi instead?

**Tags:** riichi-mahjong


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## 3 answers

### Answer by username_1 on 2012-09-26. Score: 9 | Accepted answer

Calling *ron* does not give you a *yaku*. What it will do is increase the *fu* count of your hand, but only if the hand is closed. However, winning from a *ron* on an open hand does not increase the point value at all; contrarily, you could instead claim a 2-*fu* bonus by winning on a *tsumo*.

Once your hand is opened, the only way to win is to have a *yaku* that does not rely on a closed hand. Opening your hand before you have a guaranteed *yaku*, or a good chance of building one, is often a mistake; not only does keeping your hand closed increase the number of *yaku* you can potentially make (especially "easy" *yaku* such as *pinfu* and *tanyao*), but you also have the option of adding the needed *yaku* just by calling *riichi* on an otherwise worthless hand.

If you do decide to open your hand, some common open-hand *yaku* which can be built follow:

* **Yakuhai**: A complete set (not pair) of dragons, seat wind, or table wind.
* **Chanta**: Every set contains either honor tiles, or at least one terminal (1 or 9) tile.
* **Itsu**: Three melds "123", "456", "789" of a single suit.
* **Honitsu**: All tiles, except for honor tiles, comprise a single suit.
* **Toitoi**: Every set is either three or four of a kind (i.e. no *chi* melds)

Some rulesets also allow a *yaku* for an open *tanyao* (no honors or terminal tiles). There are of course others, but I find these listed above are typically the easiest to make on an open hand, especially if you open early.

Even if you can't memorize all of the *yaku*-bearing hands yet, it's worth it to at least memorize these ones for when you choose to go the open-hand route.

---

That said, given the (incomplete) description of your hand, your best bet would've been to wait for a third dragon so as to claim a *yakuhai yaku*, and hoping to complete a pair involving one of your two bamboo tiles (while tossing the other). Calling *chi* on the bamboo actually harmed your hand, since you no longer had any reliable way to form any *yaku*.

Not knowing the makeup of your open melds, I don't know if calling *chi* on a `I Bamboo` (instead of a `IV Bamboo`) would've completed a *chanta* (or possibly an *itsu*) hand; even if it was possible, it would still be a risky wait as passing on the `IV Bamboo` (while waiting on the `I Bamboo`) would put you into *furiten*.

> **Comments:**
> **username_0**: Thank you! I must have misinterpreted the rules and somehow I was sure, that with an open hand I can't call tsumo without apparent yakus, but I can win with a ron. You have clarified this to me perfectly - now I understand. Thanks!  
> **username_2**: It may sometimes be useful to open your hand as the wall shrinks, even if you won't meet the yaku limit, simply to ensure your hand is in tenpai. This nets you points on an exhaustive draw.  A partially open hand in temporary furiten (by passing on a completing tile) can call a meld that would be a duplicate to end the temporary furiten (instead of waiting for a turn to pass).  As well as that, some rule sets will provide yaku for "events" rather than hands - for example, winning on the last draw/discard of the round.  

---

### Answer by username_3 on 2010-11-10. Score: 2

I found [this page](http://www.ofb.net/~whuang/ugcs/gp/mahjong/mahjong.html) that explicitly states the problem in the OP.

> Essentially, certain properties of the hand give multipliers (yaku [役]). At least one multiplier is necessary for the hand to win.

Multiplier, or "fan", is based on properties of the hand or how it was won (yaku). For instance, a fully concealed hand (menzenchin tsumohou [門前清模和]) gives 1 yaku, so the win condition is satisfied. In the example given in the OP, no multipliers apply. For a list of multiplier sources, see [here](http://www.ofb.net/~whuang/ugcs/gp/mahjong/mahjong.html#multipliers).

Other common sources of yaku include:

* fanpai [翻牌] / yakuhai [役牌] - "Pon of honors" - A tri or a quad in any element / the round or position wind.
* tanyaochuu [断幺] - "No Terminals" - A hand with no terminals/honors. (Sometimes required to be closed though - this depends on the actual rules in effect)


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### Answer by username_4 on 2021-06-17. Score: 0

The OP may have confused Ron with Riichi. If you declare Riichi (hand is in Tenpai - one tile from completion), then stealing the last tile with Ron satisfies a Yaku. But it is the declaration of Riichi that is the Yaku in this situation, and not the final Ron call.


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