The Search for Planet X ★★★★ | Review

The Search for Planet X Board game cover

For more than a hundred and fifty years, scientists have wondered what lies beyond the orbit of Neptune. By measuring the movements of comets, locating gas clouds, and checking for the presence of asteroids, they hoped to find proof of the existence of a new planet. The Search for Planet X translates this quest into the language of logical deduction games, building from the base of Cluedo and greatly surpassing it.


At the start of the game, we are given an empty map. It represents the observable space within our solar system and is divided in sectors. Each can have up to one comet, asteroid, dwarf planet or gas cloud, which leaves Planet X hidden in one of the apparently empty spaces left over. Our goal is to publish our findings, racking up points, without ever forgetting that the title planet is the biggest prize.

In order to find these elements, we have three actions at our disposal. First, we can sweep several sectors of the sky with our telescope to know how many items of that type there are in that space. The second option is to hit the books and learn about the relationship between one type of element and another. Lastly, we may focus our lenses on a single sector to immediately know what’s hidden in it.

The most precise information we seek, the more time we’ll need to get it. In practical terms, it means abstract and probabilistic information is easier to obtain than hard data. Triangulating the position of gas clouds through a partial sweep, the most likely position of an asteroid and a misplaced comet, is both possible and more rewarding than straight elimination would be.

Here’s the brilliant part: Your opponent’s actions are part of that fuzzy information. When we take an action, we must publicly announce what we are looking for and where. However, the answer is given privately through an app. Unlike other deduction games, Planet X doesn’t hand out our information to others. It lets us peek and try to get the jump on the opposition, but only if we figure out what’s going on.

After all, we might not know what our opponent found, but if she stopped looking for asteroids, she might have found some!  This kind of angle-shooting is what makes the game special.  Each element in Planet X has a rule to promote it. Asteroids must be adjacent to one another. Comets only appear in certain sectors and dwarf planets prevent the title element from being next to them.


However, what separates The Search for Planet X from most deduction games is the constant need for answers. Every couple of turns we’ll be asked to submit theories about our solar system. If we know about the placement of a comet, asteroid, or anything of the sort, we can place a facedown chit on the board for publication. After a while, they are revealed and checked for correctness.

This is where most of the points come in. Planet X, while a big boost, is not enough on its own to win the game. In fact, if you are too focused on it, you’ll never amass enough points to get ahead. The world of academia is restless and demands for publications come earlier than anyone is comfortable with. Often, we’ll be forced to submit without being completely sure.

Thankfully, there’s only a small penalty for submitting nonsense. Gambling on a likely result and piggybacking on someone else’s work are both solid moves. The fact that theories are played face down but not revealed immediately again promotes angle shooting. Do you dare guess what your opponents have played? Or do you mistrust their own deduction skills?

This constant scoring is extremely important. Like Cryptid and many other logical deduction games, The Search for Planet X draws from the tradition of Cluedo. However, the murder mystery classic has a mortal flaw: Everyone has access to the same information and, hence, is in an equal position to solve the crime. And since solving it wins the game, the whole play pattern becomes distorted.

My notes from a beginner game

By publishing theories, Planet X gives us the chance to distinguish ourselves from other players. We can obtain more information, play better, and see real differences in scoring. It prevents the tired problem of rushing to an incomplete solution because a 50% chance of getting things right is better than being beaten by another player. In fact, being the first to discover Planet X doesn’t present an advantage at all! Once anyone finds it, everyone else has a chance to do so as well.


The Search for Planet X does not solve all the problems with its genre. Like most of its brethren, it remains a purely mathematical experience. It may have some interaction between players, the race to find the namesake planet might be interesting and the need to publish may tie it all, but it is still just a puzzle.

I would have liked to see some other detail to push it further. It lacks the gripping narrative of Sherlock Holmes Consulting Detective or the villainous human opposition that characterizes Tragedy Looper. Even when playing the expert mode, which increases the size of the board and has ultrawide sweeps, I’m still left wanting a bit more. Just the addition of a new tricky element would do wonders for the game.

Still, it is a fantastic title. It might even be one of the best releases when it comes to raw logical deduction. It’s clean, well-made and the accompanying app and note sheet are perfectly done. It has gotten better with repeated play and while it’s not at its best at either count, it does have the possibility of playing it with just one or two players. It even features a range of difficulty settings.

The Search for Planet X might not fulfil our deepest space fantasies, but it does excel at what it tries to do. Every time I’ve played it, I’ve walked satisfied and hoping to do better next time. Space research might be a cold logical exercise, but it’s a great one.

DESIGN Matthew O’Malley Ben RossetART James Masino
Michael Pedro
Foxtrot Games
Renegade Game Studios
Maldito Games
LENGTH75 minutes
1-4 (Best with 3,4)SCORE★★★★


  • I wouldn’t compare it to games like Sherlock Holmes, those are cooperative story driven puzzle games. The rivals are more games like Cryptid which I find a slightly better puzzle but a much weaker theme.

    • While they are both fairly different games, the reason I compared Planet X to Tragedy Looper and Sherlock Holmes CD is to show a game can be a good puzzle while also having a little extra that separates it from others. This is not to say a pure logical puzzle can’t achieve the same heights, but I would need something comparable for Planet X for it to rank as highly on my mind.

      Sadly, I did not enjoy Crpytid. I found it extremely dry but, above all, I found its design made it very hard to visualize clues. It’s meant to be played without a note sheet, which I find too much for my memory and leads to mistakes. And if you do play with one, the ideal design is to list down all possible clues and every single hex and cross them out one by one. Which is a lot of work!

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