Each week, I’ll be going through the replays of a different Tenhoui, looking at key positions and trying to understand the thought process behind their decision making. The Tenhoui I’ll be examining for this week is the newest one, yoteru, who is a semi-famous Mahjong blogger/researcher. From what I’ve seen, he plays relatively textbook, with a very well-rounded style grounded in strong fundamentals, so he is easy to learn from.

Player: yoteru, the 18th Tenhoui
Twitter: https://twitter.com/yoteru11

Previous Hanchan Analysis:

• East Round
• South Round

Replay: https://tenhou.net/0/?log=2020102120gm-00a9-0000-d5d6fe8a

East 1-0

Instinct: Cut 9p. Our main options are cutting the 12m penchan, dropping 9p, or cutting the floating 3s. Cutting the 12m penchan reverts back to 3-shanten, though we do have some decent shapes as compensation. However, as dealer we’d like to declare riichi ASAP, so it’s a little too slow. If we could draw around the 3s with 2s/4s, we could get rid of the penchan neck and have a very strong set of five blocks. So this leaves the 9p: it’s part of the 579p ryankan, but two 8p have already been cut, so the 8p ukeire is weak, and drawing into 8p -> drawing into 36m means we’ll have to part with the aka dora.

yoteru: Cut 3s. As dealer we want to click riichi ASAP, so we want the strongest ryanshanten ukeire wise. Both simocha and toimen have cut 8p, and it’s unlikely that toimen or simocha onto another 8p, so we should assume 2 wall. While keeping 3s and drawing into 24s would be nice, it doesn’t warrant weakening the 579p, and the 6778s shape already provides plenty of ryanmen improvements as it covers all the upper souzu tiles. There’s also still a decent chance we draw into 4p+8p and create two mentsu in pinzu, which lets us use the aka dora.

Takeaway: Don’t restrict yourself by forcing around the dora. Just because tiles are visibly cut, does not mean they are bad wall. If the blocks you currently have are mostly strong (ryanmen, ryankan), then even if there’s a weak block remaining, it’s probably not worth losing direct shanten advancing draws to pursue building around floating tiles.

East 2-0

Instinct: Our blocks are 79m+11p+23p+3356s+3m6p (float). Our hand is pretty cheap right now with no dora, so drawing into yakuhai and calling for a 1k hand and playing to pass the round seems like a decent option to leave open. That leaves us with 9s, which isn’t really doing much.

yoteru: Our hand is fast enough to play menzen, so we should look to advance normally and aim for riichi. It also has decent value outs – we can use all three aka + four regular dora. The chance that we miss all 3 aka + 4 dora + ~40% for ippatsu / ura dora is very unlikely. With all that in mind, we should look to sakigiri the yakuhai to ensure our hand is the fastest. Even if east/chun do get called, we can pivot our hand to respond to that threat later.

Takeaway: If you’re planning to play menzen, discard the yakuhai early so your opponents have the lowest possible chance to call (assume ~10% per yakuhai in the opening 3 discards). When judging the value of your initial hand, consider what the hand might look like a few draws down the road, instead of focusing on what it looks like right now. With enough value outs, chances are you will draw into one of them. Don’t settle for cheap 1k hands when you have realistic odds at getting 3han+ riichi hands, especially in East round flat situations with no obvious threats on the table.

Instinct: Cut 7m tsumogiri. 6p is floating, but we want value to fight these open hands, so we want to leave the aka 5p + 8p dora outs open. 7m is safe to kamicha and should also be relatively safe for simocha, who likely only has value if they’re going for honiitsu.

yoteru: Cut 1p. There’s no guarantee that simocha is going for honiitsu and not tanyao, especially given the ordering of their discards (safe tile Nan -> 2p -> 8p -> 5p). With the dora cut and their discard order, we have to assume iishanten/tenpai. The fact of the matter is that we’re still ryanshanten with a bad shape (79m), and have to drop some awfully dangerous tiles to get to tenpai (6p+5/6s). So we should assume the worst here and fold with 1p, which is safe to both kamicha and simocha. Dealing in from this shape would be foolish.

Takeaway: Treat open calls with caution, especially if the accompanied by scary discard piles. As always, pushing from ryanshanten when your opponents are likely tenpai is generally a bad idea.

East 3-0

Instinct: Pass. We have a mangan/haneman chance with fairly good shapes and a lot of potential improvements around the pinzu, which is our current bottleneck. Calling for 2000 / 3900 max with aka 5m draw is not worth it.

yoteru: Call 7s. Normally this would be a pass, but there’s some specific pieces of information that make this a call. Our current wait 6p is genbutsu for the dealer, so if they declare riichi, it’s decently likely to come out from the other two players. Their discard pile is also extremely scary, having just cut the 2s dora, so they’re most likely iishanten and possibly even tenpai. With all that in mind, we want to speed up and disarm their hand. If oya wins their hand, they’ve basically secured 1st, and if we end up fighting into them and dealing in, there’s a pretty good chance we’re ending this hanchan in 4th.

Takeaway: Make sure to look at the board and consider your opponents’s hands when deciding whether to call / pass up, instead of being greedy and only looking at your own hand. Especially given Tenhou’s harsh 4th place penalty, it’s usually best to play to avoid the worst case scenario.

Instinct: Cut chun tsumogiri. We already have xia as our safe tile.

yoteru: Our blocks are already confirmed (79m+78p+34s+12345p). Both kamicha’s and simocha’s discard piles are mildly scary, and simocha has called once, but they both still don’t look tenpai. Since we have a decent shot at a fighting hand, we want to sakigiri the 4m while both kamicha and simocha still don’t look tenpai. If simocha calls the 4m or kamicha’s hand shows any sign of advancing, and we draw into a dangerous tile, then we can fold.

Takeaway: Don’t get lazy and instantly tsumogiri because you drew into a tile you don’t need, Look to sakigiri and slim down if there are opponents with open calls or scary discard piles, but they don’t look tenpai.

Summary

• If you already have five blocks that are relatively strong, it usually isn’t worth weakening one of those blocks for the potential to draw around one of your floats.
• Give open calls the respect they deserve, especially when the corresponding discard pile looks dangerous, or you don’t see many dora.
• As always, general rule of thumb is to avoid pushing from ryanshanten if one or more of your opponents look tenpai.
• Look closely at the board for threats and gauge the distance between your hand and your opponents’s before deciding to call/pass. We’re playing a four-player game, not solitaire.
• Don’t get lazy and automatically tsumogiri tiles that look unnecessary! Make sure to properly consider whether or not it’s more valuable than another tile in your hand before cutting it.