Creating an interactive lesson from your favorite player in minutes

With the occasion of William Graif's reaction video to his first video, I am also revisiting one of my first studies based on that video. Some user even said it was crap! :)

A year ago

I had just developed the feature of an extended interactive lesson, in which you could load a PGN with all possible variations and play them ALL, not just the mainline, and I came with this study concept called "Play like..." in which I take the games of a player and let you play like them.

However, I had to somehow find a way to:

1. get the games
2. filter them for a specific opening
3. choose the ones where the player was winning or at least getting an advantage
4. squeeze in the few thousand move limit for a study chapter that Lichess has

At the time I was telling people how "simple" it all was to get all the games of a player, load them in Notepad++, mark the ones you want with regular expressions, filter artifacts, remove moves after a certain ply, copy paste into a study and ta-daa! You got your work cut out for you. God bless @Dsoul20 that he took this to heart and created a lot better studies than I could have.

Back to the future

However, a year has passed. Now LiChess Tools offers you the PGN Editor feature, which can handle megabytes of PGNs, merge and split them, search for PGN and FEN patterns, even evaluate branches and filter by that. You see, even if you filtered the winning games by the PGN Result tag, you could still get all of the stupid games where your player won on time or some other reason, even if they played badly. Now you can actually filter out the branches with low eval!

So, coming back to @wgraif's Busch-Gass gambit, let's use PGN Editor to create a new study with an interactive lesson with all of his games in that opening where he was winning or equal after move 20. It's a lot of steps, but all of them are very very simple and require no extra knowledge.

1. install LiChess Tools - it works on any Chromium based browser like Chrome, Brave, Edge, Kiwi (this one is on mobile) and others
2. get William Graif's relevant games
   1. open lichess.org and search for Graif's profile
   2. go to the new (and stupid) hamburger menu top-right and choose Export games
   3. choose color=Black, uncheck all non standard chess variants, maybe even ultrabullet and bullet, which are not really something you should learn from
   4. include whatever you want, in this tutorial we will actually not use the PGN tags as in the previous method, but you might be interested in them as well as the opening and the evaluation
      
   5. press Download
3. prepare your settings
   1. click on the user menu and open Preferences - preferably in another tab
   2. click on LiChess Tools
   3. enable Advanced properties
      
   4. search for Custom analysis engine depth and set it to 16 - 16 is usually enough, you might want to set it higher, but it will take longer, it's the depth that the games will be evaluated with
      
4. use PGN Editor to generate your PGN
   1. open PGN Editor - after you installed LiChess Tools it should be an additional entry in the lichess.org Tools menu
   2. press Upload and select the file you just downloaded - for me it shows 2360 games for Black
   3. press Search and filter by Busch-Gass - the list of moves for the gambit is 1. e4 e5 2. Nf3 Bc5, you can search with that PGN, you can search just with the moves, but we will use the most effective tool, search by FEN, as the same position can be reached in several ways. So search by rnbqk1nr/pppp1ppp/8/2b1p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq . The more astute of you will see that this is the EPD, the FEN without the clock numbers at the end. - with the move list I get 354 games, with the EPD I find 355
   4. press Result - search only marks the games as Found. Result will eliminate the others.
   5. press Cut and enter ply 40, which means delete everything after move 20 (a ply is a half-move) - with 355 games we might squeeze in a Lichess chapter, but most of the time we probably won't. Also, we want to learn the opening, not play the entire game.
   6. press Evaluate and wait until all the games have been evaluated - about 3 minutes on my laptop - this will add an "eval" comment in the last move of each variation
   7. press Cut again and use this: eval>0 - this will eliminate the branches that end with an advantage for White (positive eval) - 263 games remain, which means an impressive 74% win or equal rate for Will
   8. press Merge - finally this will generate the PGN
   9. press Copy (or copy it manually from the editor) - this will copy it into your clipboard
5. create the study chapter
   1. go to any existing study or create a new one
   2. select Add another chapter and select from the Black perspective and Interactive
   3. select the PGN tab in the chapter form and paste the PGN
      
   4. create the chapter
6. learn to play like Will Graif
   1. open the study
   2. go to the chapter you just added
   3. press Preview
   4. Play!
      

OK, maybe this may seem daunting to you, so here is the final result. Maybe this one will not suck!

WGraif's Busch-Gass Gambit revisited

Enjoy the study, the extension and always... Let me know what you think!