Full repertoire using PGN Editor, Explorer Practice and Bookmarks

You are trying to learn a new opening, so you get a few theory lines in, you learn what to do in each situation, then you go play it out. And everybody seems to be moving in some other way than expected, making you feel unprepared. In this post I will let you know how to test your openings with real game data from the Lichess database, create a large PGN chapter with the moves, normalize it, then split it into theory chapters with minimal effort.

To do this you will need to have the LiChess Tools browser extension installed on your browser.

For this demonstration I will use the Busch-Gass gambit opening, as played by Will Graif.

Step 1: Gather the data

There are many ways in which to gather the data. One of them is to play the opening again and again, then download your own games. Or maybe find someone who played that opening a lot and download their games. Another yet is to use the Explorer Practice feature that LiChess Tools provides.

Using downloaded games

Let's download the games we need. Go to Will Graif's account and export the games we are interested in:

The Busch-Gass gambit it a gambit for Black. We also need only standard chess games, with the Opening tag supplied:

Game exports are pretty slow with the Lichess UI, so wait until it's downloaded. At the time of this writing, the output is a 4MB file in PGN format.

Then we will be using another LiChess Tools feature, the PGN Editor, which you can find in the Tools menu of Lichess:

Now follow these steps:

1. press the UPLOAD button or drag the PGN file in the PGN Editor's text area
2. press the SEARCH button and input Opening*=Busch-Gass - this will search any games with a tag called Opening containing Busch-Gass
3. press the RESULT button - to keep only the found results

At this point you will have a list of all games that Lichess thinks they are Busch-Gass. At the time of writing, there were 345 games.

However, an opening name is calculated based on the moves that reached the position. It's better to find games based on positions.

For this demo I will be using the typical position of the Busch-Gass: rnbqk1nr/pppp1ppp/8/2b1p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3. Just use rnbqk1nr/pppp1ppp/8/2b1p3/4P3/5N2/PPPP1PPP/RNBQKB1R as the search string in step 2. This time, I got 461 games with this search, Why? Because even if the game started with the Busch-Gass, in the end it transposed to the Italian Game four knights or something else. That is why my recommendation is to use the FEN search, not the opening string.

Let's proceed. We have a list of 461 games, but we need a repertoire. Follow these steps:
4. press the MERGE button - this will merge all games into one single PGN with many variation
5. press the CUT button and input ply 40, tags - this will remove any moves after ply 40 (move 20) and all PGN tags
6. press NORMALIZE - this will relocate all moves made from a position to the first occurrence of that positions in the PGN

At the end of these steps you have one large PGN with a maximum depth of 20 moves (40 ply) and 11940 moves in total. At the moment Lichess allows importing PGNs larger than the maximum number of moves allowed to be entered manually in a PGN chapter, which is 3000. In the future it might not. Also, be aware that if you try to make any move that is not already imported you will not be able to, as we are already over the limit. To get around this you might want to CUT to a lower ply, like 20 or 16 in step 5, or find some other way of limiting the number of moves.

And now we want to know which position is good, neutral or bad:
7. press EVALUATE - this will add comments with the engine evaluation for all moves at the end of variations
This will take some time, as the engine is evaluating each of the 544 end positions in the variations. You can skip this if you want and maybe do it later, as LiChess Tools also provides this functionality for study chapters. This function will use the engine depth configured in the Preferences -> LiChess Tools section. You can set it to a smaller number to get this done faster.

It is a good idea to save the result in a file, for future reference:
8. press DOWNLOAD

And this is how you have created a body of moves for the Busch-Gass gambit. Now let's see how you can do it with the Explorer Practice.

Using Explorer Practice

Follow these steps:

1. go to Analysis Board
2. make the moves leading to the Busch-Gass gambit (1. e4 e5 2. Nf3 Bc5)
3. go to the FEN section under the board and add a space then press Enter
   

At this point you should be in an Analysis Board starting with the Busch-Gass gambit. Continue:
4. open the Opening Explorer:

5. configure it to your specifications (you can use the Snaps! feature to quickly toggle between different settings). You want games that are not bullet and a rating bracket that is around your own rating or larger:

6. press the little "arrow in target" icon in the first Explorer tab:

Now the computer will play moves that are likely to be played by your opponents, as long as there are moves in the Explorer. So let's say that in a position there were 3 games played: in two of them h5 was played, in one of them a5. This will lead to LiChess Tools making either the h5 or a5 moves, with a 66% probability to play h5.

All you have to do now is actually play the opening. When you reach a point where there are no moves left in the Explorer, just go to the beginning and continue playing. This way you will get a large move list of actual play at your own rating. You can then take the resulting PGN and do what you did for game lists, starting with step 6. (NORMALIZE)

Creating the study

With the PGN cleaned, normalized and evaluated, you can now copy it and paste it into a new study.

1. copy the PGN in PGN Editor (the COPY button or just select and copy)
2. go to Learn and Study, then My studies, then the big green plus sign
   
3. name your study, something like Busch-Gass repertoire and choose your study parameters, then press Start
4. name the first chapter, something like Initial PGN
5. go to the PGN tab and paste your PGN there
6. select the Orientation as Black and the mode of the chapter Normal analysis then press Create Chapter

Now comes the fun part. You could just set the chapter to Interactive Lesson mode and, with the LiChess Tools Extended Interactive Lessons feature, just play against the moves in the PGN. Unlike the default Lichess functionality, every move in the PGN is considered good and any variation may get picked as a reply to your moves. However, it would be hard to follow the result, as we set up to build a repertoire, not just a Busch-Gass knowledge test .

Using bookmarks

Lichess has a recent feature that collapses/expands variation trees. The LiChess Tools bookmarks were implemented before and they bring a lot more functionality. Using both features simultaneously might be really confusing, so I recommend to enable bookmarks and also auto-expand - which effectively disables the native collapse functionality - in the LiChess Tools preferences:

Now, with the Explorer open to your desired specifications, let's separate the variations:

1. go to the start position in the chapter
2. press right-arrow repeatedly until you get to the Busch-Gass starting position (if that's not already the start)

Because you used NORMALIZE, all the moves that continue from the position will be clustered on the move list node on the mainline. Any transpositions will be shown as branches that end at the transposing position.

Now you should see a list of moves that have been made by opponents in that starting position. They are not in the order of their most common use, only in the order of the games merged in the PGN Editor, though. So let's look at the Explorer to see which is the most common move made by people. In our case, the most common response is 3. Bc4. Let's mark that as the main line:
3. right-click on the 3.Bc4 node and select Add/Remove bookmark
4. add a name for it, like Symmetrical (most common)

Now, what does that do? Several things:

• it gives a name to the variation
• that label can be used in the study chapter URL as a link (right click on it and select Get bookmark link (you will get something like https://lichess.org/study/STUDY_ID/CHAPTER_ID#Symmetrical_(most_common) )
• it allows collapsing of all of the moves following Bc4, which will also be persisted during page refreshes
• it allows splitting the following moves into a new chapter (we will be using that here)

Let's repeat the process for the next relevant moves:

• Nxe5 - Greedy (best)
• d4 - Aggressive
• Nc3 - Vienna
• c3 - Cautious

Note that these are not the names of the variations, if they are named in any way, it's something you yourself are creating and are free to name however you want. From the 12000 moves I started with, now the move tree looks much nicer. But still, each of these 5 variations have different characteristics and plans. I would like to explore them separately. Let's split them off.

Go to each bookmark, in the order of their importance:
5. right-click node and Shift-click Split chapter here (pressing Shift will delete the variation from the chapter and create a new one. Without Shift the moves will just be copied to a new chapter and remain in the initial one)

At the end of this process, you will have the following chapter structure:

Without the most common five lines, there are only 445 moves remaining in the main PGN. You can decide what to do with them. For this demo, I will copy the Initial PGN chapter into a new one called Minor variations, where I will remove the empty bookmarks and leave whatever is left, then remove the moves after the minor variations in the initial chapter and rename it Start.

In the first chapter, now only the main moves remain, with comments linking to the newly created chapters. With a little arranging, this is the final result:

Conclusion

With the many features of LiChess Tools you can improve your chess with simple and clear steps. It's a completely free browser extension and it will remain so forever. These are just a small subset of provided functionalities. If you want the nitty-gritty details, every feature is described in the LiChess Tools User Manual

As always, enjoy chess, Lichess and LiChess Tools and let me know of your experience and ideas!