Question: The [Einstein's puzzle](http://www.stanford.edu/~laurik/fsmbook/examples/Einstein%27sPuzzle.html) or [zebra puzzle](http://en.wikipedia.org/wiki/Zebra_Puzzle) is a well-known logic puzzle. Are there any very easy ways to solve it fast?

Answer: 
For small puzzles of this type, a grid is very useful. If there are three types of item, with five of each type, you can use a grid like this. Put an x in all the squares you know cannot hold, and fill the boxes you know are true. So if you are told 1 is not a, you x the upper left box. If you are told B is 2 you fill the corresponding box, then x all the boxes in the same row and column. You can also copy x's from one grid to another when you fill a box. For four types, put types 1,2,3 across the top, 4,3,2 down the left and you will have six grids. It becomes unwieldy after five types![like this](https://i.stack.imgur.com/Sg0fp.jpg) This is especially useful to see when you have eliminated all but one possibility. To capture the left/right information, one of your types of item can be the house number.
This answer is more about choosing the puzzle than general strategies. Once you have the grid, a lot of reduction tactics are the same as with Sudoku.

Playing around with timed versions of the Einstein puzzle like [this](https://www.thinkpenguin.com/gnu-linux/einstein) can soon net you shortcuts for solving the grid. Granted, you get everything laid out and can start solving immediately, but our brain is more suited to certain types of cues. Some solved squares may help, but it all depends on its position and the other cues. Particularly the "X is between A and B" hints can be very helpful, especially when they are chained or you can place them immediately. Since most hints are relative, you get several new anchor points to try out. Perhaps their higher apparent benefit is also due to the way we process information, as they usually clear the most amount of possibilities upon placement and the same amount (2) as is-before when uncertain, reducing the problem space. In general, if you can solve any of the near-central squares, that can reduce the positioning options of the triplets significantly.

During plays, I've noticed a particular pattern that I can solve fast (as opposed to 15+ minutes). All my best time (2 min) games started like this, but I don't know if the speed can be attributed to just the initial layout. It's when you start with a solved square one square from the border that can be expanded with an in-between cue. It's better than border squares, since you can then also discard some guesses via is-a-neighbour cues, but still gives only one possible orientation.