#shiftcombine

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A final multi-step shift-combine

RURU, with the benefit of happening to do excellent color-matching along the way.

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Multi-part two-tile shift-combine

Not all shift-combines must hit three columns' worth of blocks. From this position, RRU will combine ThreeJays (192s) into the top row's third column and Trevens (96s) into the top row's fourth column.

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Multi-step shift-combine

The shift-combines we've posted earlier have been two-step (RU). This one is three-step: RUU. The first R combines 3s in the right column under the 6, and then going U twice will combine those 6s into the 12 in the top right corner to make a 24.

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192 shift-combine

With nice color-matching!

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Dat shift-combine

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The shift-combine

As discussed in the previous post, the natural tendency is to try to build material up into the top row via the far corner. But don’t be deceived! As tempting as it feels, it’s rarely correct. We present here a fairly advanced technique, in the spirit of alternating between basic strategic building blocks and more advanced ones. (Don’t worry, sometimes we’ll just do pretty pictures too.)

The best way to aggregate material in your top row is via the shift-combine. This is a move wherein you combine multiple blocks up from the second row into the top row with one move. In order to do it, you need to first line up blocks in your second row that match the ones above them in the top row. This is usually accomplished by moving Right and then Up - hence, the shift (Right) and combine (Up).

In this gif, you can see the shift-combine happen at the end. The player is building up her second row like a mirror of the top row, but with the biggest block being equivalent to the second-biggest top row block.* When she has everything in place, she completes the mirroring by moving Right, combining her Treycees (12s) into a Tristine (24) and then combining the resulting second row Up with the top row.

Though the shift-combine is a difficult move to master, the payoff is huge. The alternative (combining material leftwards across your top row) leaves a gaping hole at the right side, which will be quickly occupied by incoming filler blocks (1/2/3). Having such small blocks in your top row can be a big problem, since it can become hard to move large material out of the middle of the board.

Over the next day or two, we’ll post some pretty stills of successful shift-combines to illustrate the point, in (many) fewer words.

*This is a common pattern, where your top row is occupied and you wind up playing what is effectively a sub-game in your bottom three rows at a lower level.

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Why Rounding the Corner is Basically Impossible

Early on it can be tempting to try to "round the corner," i.e., to move material rightward across the second row and then combine it up into the top right corner. (Remember, we happen to use the top row, so those of you who combine along other axes can translate to your frame of reference.)

Rounding the corner is problematic for two reasons: it is difficult to execute, and it often leaves you in a sub-par end state. Note that to successfully round the corner, the 8th slot (far right of the second row) has to be free to shift the matching block over and up, as shown at the beginning of this gif. Threesus does not grant that state often.

If you successfully round the corner, the smallest blocks often make their way up into the second row because they move from the third row to the second, or come in from the left. If you have larger blocks around, you risk death via checkerboard. Lesson: don't rely on rounding the corner! The shift-combine is much safer. What is the shift-combine...? Stay tuned.