Tips and Tricks

[TazY2]

What tips and tricks do people use to get faster times? So far, I'm on the higher side of average, but want to go faster...

[manicann]

Hi TazY2,
The first thing I do when I start a puzzle is mark every square that doesn't have a tree to the left, right top or bottom as dirt. Then look for squares that have an obvious solution. Other squares can be ruled out as well. Find a puzzle size you are comfortable with and keep playing, you will get faster.

[Alexequith]

I'm looking for some tips as well.

[bocci]

I am an average player. I play on an Android, where a 15 x 15 is as big as I regularly play, due to screen size vs width of my fingertip. Anyhow, here is a simple tip or two to help struggling beginners along.

1. FILL THE OBVIOUS. As previously advised, fill in all the squares, that by the basic rules, are obviously bare turf , or dirt. Include all squares in rows or columns labeled zero. This is shown below on a 10 x 10 puzzle.

Screenshot_2020-04-29-12-26-17.png
I'm sorry about the poor resolution. The forum's image software compresses Screenshots to a blur and when I try a page download it's incompatible, so here goes...

Since it's not readable, row nine is labeled zero. So, I've marked every square in Row 9 as bare turf. I see I forgot one square: Row 4, Column 8 (R4C8) should be turf. Please forgive that, lol.

2. ELIMINATE BRIDGES. Information from a given row or column can be used to eliminate candidates from an adjacent row(s) or column(s). Row 1 is labeled with a 3, meaning that Row 1 contains three tents, but has four areas available for those three tents. Observe that the square R2C2 connects or "bridges" R1C1 andR1C3.

If R2C2 were a tent, we would have to mark R1C1 and R1C3 as bare turf. Doing so would leave only two squares in Row 1 available for tents, so R2C2 cannot be a tent and we mark it as bare turf. Likewise, we can mark R2C8 as turf, as it bridges the other two candidates. This technique can be applied when the number of available tent spaces is EXACTLY one greater than the number of tents.

Be careful to not inadvertently break a bridge that connects a single candidate square with a field of two candidate squares. In Column 1 (labeled as 3 tents), we may not mark R6C2 as bare turf because it leaves R4C1 as a candidate, making for enough remaining tents sites.

Although it is less common, you may eliminate a bridge between a single candidate and a field of three candidate squares. Row 8 is labeled for 3 tents. If a tent were placed at R7C4, it would eliminate R8C3 as a tentsite and would also eliminate R8C5 as a tentsite. Because R8C5 is in a group of three, this move would reduce the available number of tentsite areas in Row 8 to 2, which is incorrect, so R7C4 must be bare turf.

If you understand this general idea, you ought see that R4C9 can be marked bare turf without a second thought, because Column 10 has only four open squares and is labeled 3 tents.

Good luck!

[SeventhWave]

Manicann was right: start with marking the spaces that are definitely dirt. I have a set of rules I use to find where there are dirt blocks (which is just as important as finding tents), but they are a little hard to explain. I'll try to explain one that I think is particularly helpful. Suppose this is your situation:

Campsites3.png

Logical right? You need to find 4 tents in the 9th column, there are four white spaces, two of them are singles. So those must have a tent.

Campsites3b.png

Now the blue circle shows where a tent must go: the tree has only one cell left. The red circle is definitely dirt: the tree already has a tent. But for this example, suppose you didn't notice that.

Campsites4.png

The 7th column (red) has three tents, and four white spaces. No matter how you would arrange those tents... the cells outlined blue MUST all be dirt! Check for yourself.

This trick works for every column or row that has one white space more than there should be tents. Those white spaces can be one or two cells wide, but the trick only works on the spaces between spaces that are only one cell wide.

This lets you mark cells from adjacent rows as dirt.

I use more rules to determine dirt, but this is one that I think you should know so you can get into the mindset for finding your own rules. As you play, you will figure out more. Try and approach it by thinking logically.

[bocci]

ISOLATED TREE

Screenshot_2020-05-01-16-07-03.png
Column 5 is labeled as containing 3 tents. I think of the tree at R9C5 as isolated, for it has no trees immediately diagonal to it which would make for additional tent site candidates. Therefore, R8C5 and R10C5 cannot both be tent sites. It's also possible that neither is a tent site given the open square at R9C4. The idea is that you may count those two open C5 squares as only one potential tent site combined. Moving upward, there are only three other candidate tent site fields in column 5, making a total of 4. As a result, you have exactly one tent site field more than allowed tents in column 5, so you may fill the bridge square R5C4 as bare dirt.

Good luck!

[bocci]

BARRIERS

Often the edge of the board, a tree directly next to another, and areas of dirt are constraints which help to eliminate tentsite candidates.
Screenshot_2020-05-03-16-49-30.png


In the board above, square R14C2 cannot be a tentsite. If it were, it would associate either with the tree at R13C2 or the tree at R15C2, but the dirt filled in around it would deny a tent to the other tree. Therefore, we fill R14C2 in as dirt.

The same situation applies to R4C6. Placing a tent there would deny a tent to not only one, but two trees. R4C6 must be dirt.

Good luck!

[bocci]

"KNIGHT'S" CORNER.

The name is due to the position of two trees spaced apart like a knight's move on a chessboard. If one of the trees has white squares around it only in the general direction of the other, then you can mark as turf the square diagonally from the first tree. A picture is necessary of course.

Screenshot_2020-05-03-17-12-10.png
The trees of interest are at R14C4 and R12C5. R13C5 must be dirt, because, otherwise, R14C4 would be denied a tree.

These occur quite often and are simple once you start looking.

Good luck!

[bocci]

A BRIDGE and an ISOLATED TREE.

This is a bit trickier.

Screenshot_2020-05-04-11-07-10.png
Observe the center column in the game above. It contains a known tent and three fields which are candidates for tents, but it can only contain three tents in total. In a three tent, four field column, we typically look to eliminate tent sites in the adjacent columns, a tactic I call "breaking bridges". The only possibilities are the bridge squares immediately to the left and right of the tree in Row 11. But they connect a single open square to a pair of open squares. It is usually not correct to mark them as dirt. However, in this instance, the square in Row 13 is effectively a part of a two-square field AND is one of the tent candidates for the isolated tree in Row 14, so we may mark the Row 11 bridge squares as dirt. For if either of those bridge squares were tents, then there would only be room for two tents in the center column.

Good luck!

[bocci]

CORNERS.

Look for these along edges: either fixed boundaries of the board, or against trees that act as barriers.

QuickScreencapture_20200510-074002.png

Observe the lower left corner. The square R9C2 cannot be a tent because it would associate with only one of the trees R9C1 and R10C2, and would eliminate the candidate tent squares for the other tree. Mark R9C2 as dirt. When two trees straddle a corner, as depicted here, you can often apply this tip.

Notice also the Row 2, Column 14 and 15 trees. They serve as a virtual edge, creating a corner with the board edge. Like in the first example, the trees at R3C14 and R4C15 straddle that virtual corner. The square R4C14 must be dirt.

Good Luck!

[bocci]

BRIDGES, ISOLATED TREES, AND MORE.

QuickScreencapture_20200511-131508.png
In Column 4, the bottom 5 open squares can hold as many as 3 tents, and the three open fields above, 3 more. That's a capacity of six tents in a column marked for five tents. With the tent capacity exactly one greater than the number of tents allowed, we look to break bridges in adjacent columns. We immediately see that bridge square R8C5 cannot be a tent, because it would remove two candidate tent squares from column 4.

Looking further, we also see that R10C5 cannot be a tent, because that would take away potential tent sites at R9 and R11, leaving Column 4 with space for only 4 tents, which isn't allowed.

(An aside here. We just broke a bridge between one open square and a five square field. Within the usual 'bridge' rules, one may break a bridge between any two fields in a given column or row when both fields have an odd number of squares. The idea is that if both are odd, a tent bridging them will always take away a potential tentsite from each of them.)

What if we hadn't seen that last move? We could have, instead, marked R11C4 as dirt, because, if it were a tent, the tree at R12C5 would be denied a tent. That may be considered more straightforward, because it removes a square from the bottom field of five squares, leaving only room for 5 tents, allowing us to mark R7C4 and R9C4 as tents. There are other mitigating factors to do with the row markers not shown, but the point is sometimes there is more than one path to a solution.

Now to Column 1, with its isolated tree at R2C1. Either R1C1 or R3C1 must be a tent, which helps us with Column 2 and back to Column 1 as follows: either R1C2 or R3C2 must be a tent, but not both. This reduces column 2's tent capacity to 6, exactly one more than the indicated 5 allowed, so we can look for bridges: we see that R8C1 can be marked as dirt.

Then R10C1 is a tent, and R13C1 is dirt.

Good luck!

[bocci]

Multiple ISOLATED TREES

QuickScreencapture_20200525-073120.png
Note that Column 3 contains only one tree, and because there are adjacent trees at R8C2 and R8C4, we know that the single tent in Column 3 must be at R7C3 or R9C3. Therefore we have filled all other Column 3 squares as dirt.

In Column 2, seven open squares are candidates for five tents. But, counting from the top down, note that the 2nd, 3rd, 4th, and 5th of those seven open squares can contain, at most, three tents . Therefore, we know that the other open squares R1C2, R12C2, and R14C2 must contain at least two tents, maybe even three, which tells us we can fill R13C1 in as dirt.

Good luck!

[bocci]

Filling more open squares from the last example. Here it is again.

QuickScreencapture_20200525-073120.png

When we filled most of Column 3 with dirt, we also created a sort of backstop or border abutting Column 4. Borders help us! Especially the dirt in squares R4C3 and R5C3.

We see now that square R4C5 cannot be a tent, because filling in dirt around it would deny an open tent square to one of the two adjacent trees. Also, square R6C5 cannot be a tent, because that would deny the tree at R5C4 a tent.

Good luck!