Anyone with an interest, however fleeting, in video games, smartphone apps, or pop culture has perhaps noticed their Twitter feed being slowly overtaken by images featuring cartoon cats, whimsical colors, and text in Japanese.

My landlord will only let me own two cats, but Nekoatsume has my back in the "wish fulfillment" department pic.twitter.com/zNNRCusTsV — Katie Chironis (@katiechironis) June 9, 2015

GUESS WHO HAS ALL THE CATS IN NEKOATSUME IT'S ME OKAY pic.twitter.com/BraIapx8WM — Adi Robertson (@thedextriarchy) June 11, 2015

What you're looking at is a game, which should be obvious. But what may not be obvious is what the game is, why it's so popular, or even how to find it — especially because it's in Japanese, and most Americans don't make a general habit of searching for Japanese titles in their various app stores.

But this game comes by its cult appeal honestly. Falling somewhere between The Sims and Tamagotchis (the briefly popular "electronic pets" from the 1990s), it makes you the best pal of a bunch of neighborhood cats, who visit your home to eat the cat food and play with the cat toys you leave out for them. It's addictive, adorable, and completely free. And it will only take up a few spare seconds of your time, whenever you need to check in — though you just might find more and more excuses to check in as you coax more cats into your virtual home.

Potential virtual cat owners, meet the felines of Neko Atsume.

What is Neko Atsume?

Designed by the Japanese company Hit-Point, Neko Atsume is a mobile phone game that gives the player a small backyard area (which can later be expanded with an indoor area as well) where the stray cats of the neighborhood come to visit. The cats will only drop by if there's food, but if they like the food you give them, they'll stay to play with any cat toys you might have laying about. These toys can range from simple balls and stuffed mice to more elaborate cat jungle gyms.

Here's what Neko Atsume looks like when you have a bunch of cats hanging around:

After they're done feasting and playing, the cats will leave you some number of sardines. These offerings will either be normal gray sardines (which they leave with great frequency) or precious golden sardines (which they leave much more sparingly). You can buy more golden sardines with real money, but the cats are generous enough that you shouldn't really have to. Occasionally, the cats will also bring you a special gift they've found in their scrounging.

The fish function as the game's currency, allowing you to buy more and more elaborate cat toys, which will attract more and more cats, who will bring you more and more fish. And on and on it goes.

The game, in its current incarnation, features more than 40 different cats. Some of them are standard cats, but others wear costumes. There's a baseball player cat, a samurai cat, and a giant fat cat who eats all your food in one go.

And what does "neko atsume" mean? Roughly translated, it means "cat collecting," according to GamesIndustry.biz.

How did people even come to know about this game?

Neko Atsume has climbed the charts in Japan, where there are enough mobile games about cats that Apple was able to run a promotion early in 2015 that centered on February 22, an informal holiday called "the Day of the Cat." It is so named because 2/22 can be spoken as "nyan nyan nyan" in Japanese, which is roughly similar to saying "meow meow meow" in English. (Yes, now you know where the name "Nyan Cat" comes from.) Though not an official holiday, enough people know about it that Apple's promotion proved a success and boosted Neko Atsume into the top 10 of all games sold in the country.

Neko Atsume's slow-building popularity in other countries stems from the American video game press discovering it. Video game writers, who always keep an eye on what's going on in the Japanese gaming industry, were quick to praise the game, which is fairly easy to play even if you don't speak any Japanese.

One of the earliest US-based posts about Neko Atsume was on the site Destructoid. The game later received writeups from outlets like Kotaku, Vice's tech site Motherboard, and Boing Boing's gaming site Offworld. Soon, the game even earned its own subreddit.

Recently, the game has begun to cross slowly but surely into the mainstream, especially thanks to this story on the Billfold, which satirizes the game's economics.

You wake up in the morning, put out cat food, painstakingly arrange the cat toys, and wait. When the cats come, they leave you a pile of dead things in exchange, as cats do. You, in turn, walk your basket of stinking fish to the market to buy more cat food and a cardboard box shaped like a car. No one drives cars anymore. You do not ask what happens to the fish you exchange for these cat toys, just like you do not ask what meat is in the thin soup they hand you, in its little cardboard bowl. That is what you eat. The cats eat food you recognize, except now someone has taped a piece of red cardboard with a cat pawprint to the can, as if to indicate that all food is for the cats now. You put out fresh sashimi, sometimes, arranged as best as you know how. The cats come, play, leave their dead fish. Another day ends.

Why is Neko Atsume fun?

Three reasons:

1) It's about cute cats. C'mon. Everybody loves cute cats. And though the animations for the game's various cats are decidedly limited, they're charming. Half the fun of the game is seeing what the cats will do with a new toy, or seeing what the latest cat you've lured to visit you will look like. The game is about collecting cats, and it has perfected the element of trying to procure absolutely every possible item/cat the game has to offer and cultivating the best possible collection.

2) You can play it at almost any time. Whether you have a few minutes between meetings at work or you're on a flight, you can play Neko Atsume. It doesn't require a data connection, and checking in on the game can be done in as little as a few seconds. (Do the cats have food? If not, refill. Are there any cats present? If so, take in their majesty.) The platonic ideal of a smartphone game is something that can be played pretty much at will, and Neko Atsume comes very close.

3) It's hugely customizable. You can name your cats anything you want. You can take pictures of both your cats and their entire play area. You can share those pictures with friends. You can constantly switch out the toys on offer, or stick with a tried-and-true setup. It's hard to lose Neko Atsume. Instead, the game is all about giving you the tools to create your own perfect cat garden. That's immensely appealing, especially in mobile gaming, where not having a sophisticated controller rewards games that provide players with several different options in fairly simplistic fashion.

There are, of course, lots more reasons to enjoy Neko Atsume, but the three above are a big part of why it seems to be taking over the world.

Can I watch somebody play for a while?

Absolutely! This excellent video by Kotaku will give you a good sense of what to expect:

How much Japanese do you have to speak to enjoy Neko Atsume?

Zero. The entire game is in Japanese, but provided that you know how to follow visual cues, you'll be just fine.

The one part of the game where not being able to speak the language hurts is at the very beginning, during the tutorial. However, if you simply follow the arrows on screen and keep swiping when they tell you to, you'll get through this very short section very quickly. (All you need to do is leave out a food dish and a red ball for the cats to play with.)

From there, the game features a lot of Japanese text, but it also provides plenty of visual prompts that help tell you what you're meant to do.

Consider, for instance, the game's main menu. Yes, the text is in Japanese, but the pictures are (hopefully) universal:

The little images are (starting from the top left):

1) Your cat album: Here's where you can look at pictures and profiles of all the cats you've met. It'll also give you a sense of how many cats you have yet to find.

2) The store: You'll spend a lot of time here, using your sardines to buy items like cat food and cat toys.

3) Inventory: This is where you keep the items you've purchased while you figure out where to place them in your backyard.

4) Camera: Use this button to take pictures of any cats that happen to be in your backyard, or pictures of the whole area at once. (You can also activate the camera by tapping and holding on any cat on the main screen.) Pictures of the entire backyard will show up in your phone's photo gallery; pictures of individual cats will appear in their profiles.

5) Garden: Click this button to return to your backyard to see your cats at play.

6) Sardines: Tap here to check on whether the cats have left you any sardines you need to collect. You can also access this option from the main screen, and you can collect all sardines at once by tapping the big button at the bottom:

7) Settings: This mostly lets you turn the music and sound effects volume up and down.

8) Gifts: Peruse any gifts your cats have left for you.

9) About: Learn information about the game — if you speak Japanese.

10) Change theme: If you have enough gold fish, you can use this button to purchase a new theme for your house and backyard.

11) News: Read about the latest updates to the game — if you speak Japanese.

12) Contact: Report problems and send messages, though this is yet another screen that will be difficult to use if you don't speak Japanese.

If you want to know more about what the various screens say, the blog I Wish This Day Would Never End has done a good job of translating them, as well as offering hints on how to play the game.

What items do the cats like best?

Here are three they're sure to love.

1) Early in the game, it can be tricky to find something that will draw out a significant number of cats. (The cats seem to be programmed to respond to certain items.) Perhaps surprisingly, this tiny, inexpensive orange ball seems to be a favorite of many of them.

2) Later on, you'll want to give your cats a mat or someplace to hang out while they watch the other cats play. I had the best luck with this simple purple one.

3) Once you've really got the sardines rolling in, there's no better way to keep the cats coming than to buy this cardboard house. You'll often find three or four cats hanging out in or around it.

Do the Japanese love cats?

Who doesn't love cats? If the internet has taught us anything, it's that cats — standoffish and aloof, but incredibly loving on their own terms — are the perfect animal of our modern era. So of course the Japanese love cats. It's only right.

More seriously, though, cute cats have always been part of Japanese pop culture. From Hello Kitty to the catbus in the movie My Neighbor Totoro, they appear in lots of great works of Japanese pop art. Japan was also the second country to open a cat cafe (where customers get to hang out with felines) and is the home of Maru, arguably the world's single greatest cat and one of the original viral video stars.

And remember how I mentioned that Japan celebrates an informal Cat Day? Well, Apple was only able to run the promotion that rocketed Neko Atsume into the public eye because there are a lot of Japanese games starring cats.

What does it all mean?

Smartphone games where little beings live inside your phone have become increasingly popular in recent years. From The Simpsons: Tapped Out to Kim Kardashian Hollywood, more and more apps host virtual worlds that carry on, whether you're looking at them or not.

And that's part of Neko Atsume's appeal. Even though we know these sorts of games are heavily programmed to make it seem like they exist even when we turn off our phones, if they're done well, the illusion of their persistence becomes easier to accept. The cats in Neko Atsume don't just seem like animated sprites on a phone screen; at their most convincing (and with a little willing suspension of disbelief), they seem like real cats that just happen to live within your phone.

Much has been written about how our phones and tablets are isolating us from actual human interaction, by creating a world where we're constantly looking at screens, even when we should be focused on what's unfolding before us in reality. But our phones can also make us feel more connected. Maybe that comes in the form of texting with our friends, or maybe it comes in the form of caring for virtual cats. Neko Atsume is great at constructing those feelings, even as your conscious brain is aware that the kittens you're feeding aren't real.

How do I download this game?

Neko Atsume is available for free on both iTunes and Google Play for iOS and Android, respectively. Follow the links, or search for "neko atsume" in your device's respective app store.

Correction: The original version of this post identified Motherboard as Vice's gaming site. It is a general tech site.