First things first – this game will not teach you the rules of Go. If you’re a total beginner, this isn’t the game for you: there’s no tutorial, and the documentation is very basic, so if you’ve never played Go before, please check out some of the excellent resources available on the web first. (One excellent place to start would be Reddit at /r/baduk – Baduk being the Korean name for the game.)

If you already know how to play, then the question you should ask is, is this game for you?

The obvious thing the game offers you is the AI. Rated up to 7d, this is the most powerful commercially available Go AI, and can challenge all but the most skilled amateurs. Its minimum setting of 13k, on the other hand, should match up pretty well against anyone with more than a handful of games’ experience. In addition, the game supports handicaps up to 9 stones, and based on a couple of games, it does a good job of playing handicap Go (far from universal amongst Go AIs).

So while a player of almost any skill level can get a good game from Crazy Stone, all but the strongest could do the same against any number of cheaper or free AIs available. Given that, why would you pay such a steep price for the best AI?
The reason is the item at the bottom of the features list: the Analysis Engine. Crazy Stone allows you to review and analyze games you’ve played against the computer as well as games from the major online Go servers (anything that can export a game record in standardized format). For each move you can see Crazy Stone’s analysis – including the top 20 moves it considered and the relative value of each. If you’re willing to put in the time to go through it, this is almost like being able to play a teaching game any time you want, having a 7d grade your moves.

For me, the Analysis Engine is worth the entire price of admission. I’m roughly 1k-1d strength, so I usually know most of the moves that Crazy Stones evaluates, but going through the analysis gives me tons of food for thought about the differences between them.

Technical notes: this program can use all the CPU you can give it. I’m running this on a fairly beefy CPU i7-5930K, 6-core 3.5Ghz – looking at the Analysis Engine, this allows it to simulate about 10,000 games per second. Generally speaking, it seems to take around 30,000 simulations to get a good analysis for a move, so about three seconds on this machine. I also tried it on an i7-3770K, 4-core 3.5 GHz – 7,000 games/second, and an i7-4810MQ, 4-core 2.8 GHz laptop – 6,000 games/second. So it seems like most 4-cores would need around five seconds of analysis time per move. Unfortunately, I don’t have any duo-cores to try out, but you can probably figure on doubling that time to ten seconds.

When Crazy Stone deep learning first came out, it was one of the earliest "really good" programs you could buy and play against.

It's well made, for most people very strong, simple and easy to use.
It's also possible to "review" games, and look for better moves.
It's a nice program to play for every amateur GO player and Go enthusiast out there.

But other AIs got better really fast.
LeelaZero dominates CrazyGo completely and is free and easy to use for everyone who wants.

Other negative remark about this game: it's finished.
Other AIs are still developing, but CrazyStones has never seen an update once. Ever. You can call it Abadonware.

So why buy this at 70-80EUR/USD? --> You don't, it's simple as that. Not even for 20 bucks. Maybe for 10.
A GO AI which plays 4-5D Amateur isn't worth anything nowadays.

This is a pretty good game. But with 2020 around the corner, it should really cost at most $20, not $114.95 (for me). Some things I like about it:
- nice interface & info presentation
- lots of features done well: save to SGF with move numbers, replay from a certain point as human / AI / both / neither / swapped, winning % bar, AI works for all board sizes, deep analysis (need good PC, I didn't understand it well either)
- can play offline

However there are huge cons:
- PRICE
- windows only
- AI plays weird at lower levels, not really like a player of that skill level
- no updates

I would recommend you take your $ and support online-go.com, which basically is better than this in every way:
- free
- also has good interface & presentation
- AI at every level that plays naturally like that level!
- if you donate some $ each month (like $5 = coffee), you can get pro level analysis & move suggestions at any point in game; otherwise you get 3 biggest losing plays of your game and alternatives only
- works everywhere b/c it's in browser, looks good even on mobile... (although will be hard to play 19x19 on mobile)
- all games tracked, can see yourself progressing!
- has community, play with real people if you want!
- constantly gets updated
- analysis is understandable (done post game), can be played flawlessly on the weakest of computers

These are just things from the top of my head. Only con is you can only play online. If you really need offline, you can get a free app with stronger AI, analysis, looks good (search "lizzie go").

Don't pay this price in 2019, or beyond. This really should just be $10.

has been way too expensive even when it came out many years ago, has few functions and no friendly UI at all (which could be expected at 60€), and received none of the promised updates

Strong engine, plays almost like a human - I haven't seen any funny robot-style moves yet.

Anyone except complete beginners can play against it. The lowest strength the engine can play is 13k - if you add handicap to that, then even ~20k players can get some benefit.

The user interface seems dated, but don't let that fool you - underneath it there's a great Go engine that plays a strong game and doesn't suffer from the usual issues of previous generation engines.

One issue is that the engine doesn't speak the GTP protocol, so you can't use it with a generic UI like GoGui. If they add GTP in an update, it would be great.

Incredible! I've been playing Weiqi for a while before getting this software, and now play at about 4-kyu, and I'm greatly impressed by the AI of Crazy Stone Deep Learning. I usually play against the 7d computer level on 19x19 when I have a lot of time. 6d or 5d when I'm in the mood for a quick game. 3k to 1d when I'm feeling like trying to beat a stronger opponent. The higher levels teach me a lot about the game. Mistakes at my level are quickly punished by the AI. I often use the [estimate] Territory function when experimenting against stronger levels so I can see what works and what doesn't, and why. The interface, music and sound effects are simple but quite comfortable. I look forward to The Second Edition.

Of course, I also do some study from books and videos online to make best use of my "Go" time, so I can improve faster and enjoy playing this and stronger human players even more.

Very well worth the money if you're serious about improving your game!! It's rare I can ever play a 1d+ human player in my small city, so being able to play 7d anytime as often as I like is huge for me. Thank you.

If you're a weak player, you might not like the price, and might want to buy a $10 book first, or buy an easy game instead if you're not serious about Weiqi / Baduk / Igo / "Go". However, I wouldn't discourage a beginner from buying this if serious about the game and can afford the investment. You can play against the 13 kyu level AI on 9x9, 13x13 and 19x19 boards, and work your way up the levels. (A beginner is 30-kyu but usually improves quickly.)

If you're quite strong and don't want a $20 program you can beat easily, this is well worth $80.

For those mentioning AlphaGo, you can't buy it, and it runs on a neural network of something like 2000 cores, for a super corporation's AI research and development that will someday "go" way beyond board games. So, why compare AlphaGo to $80 software you can enjoy right now?

I bought the game even with that ridiculous price tag thinking that at least it would be like the mobile version. It is way inferior to the mobile version where you can have graded games. This is a joke, right?

There's a user-defined tag for this product that reads "casual." I can't really say that this product is for the most casual observer of Go/Igo/Weiqi/Baduk.

However, what I can say is that if you're an amateur player looking for an AI Go sparring partner then here's your option on Steam. In fact, it appears to be one of the most compelling options at the moment for playing this game on Steam (the other being Tabletop Simulator if you have a friend).

Verdict: If you want to Go it solo on Steam (all easy puns intended) and practice against one of the more competent AI's on the market, here is your choice. But for $80 let's hope that future updates or "The Second Edition" will be included.

I'll recommend it for the purpose of hopefully inspiring more products such as this to hit the Steam Store. With even more hope, I'd like to see something like KGS or Tygem on here as well.

Human like play. Positional calculation is a major plus. But the program has a weakness with ladders.

Like it a lot, strength of PC player slightly overrated but this is not a big issue. Recommendation for any go player who plays the game on PC to pass the time and get a good opponent.