I have only read the first one (Idiot-Proof). It impressed me a lot! It actually offers a consistent up-to date repertoire, that in many cases will bring your opponent out of the beaten track. I didn't thought that possible in just one book anymore.
Idiot-proof Chess Opening Repertoire vs Keep It Simple 1.e4 and Keep It Simple for Black

To begin with, I submit that the reason there are no reviews comparing these books is that in order to do a respectable job that would necessarily involve a lot of research, time and effort. I believe very few reviewers would look forward to or embark upon such a project, unless compensated handsomely to do so. Consistent with my dearth of remuneration, I will leave it to the comments and links I have provided further below to assist in providing the prospective reader with some insight into the books in question.
I own Sielecki's first two opening repertoire books - " Keep It Simple 1.e4 (KIS 1.e4) and "Keep It Simple 1.d4" (KIS 1.d4). I also own Burgess' "An Idiot-Proof Chess Opening Repertoire" (IPCOR). I do not own Sielecki's "Keep It Simple For Black" (KISFB), which to my knowledge has not yet been made available in print form in the USA (however it is available for pre-order on Amazon, to become available in November 2022).
In terms of their usefulness to the chess player, my bottom line opinion of the books I own is that they will each find a receptive audience that will view them as constructive for the specific openings covered, so that in that sense none of the books are necessarily any "better" than the others. However there are significant differences, not only in the openings chosen for the repertoires, but also significant stylistic differences in their presentation as well as in the total number of book pages devoted to the repertoires.
Along those lines, I offer the following observations which I believe should be appreciated at the outset (and which can be readily deduced by examination of the content of the links below)...
1. The White and Black repertoires offered by the respective authors are completely different. There is essentially no commonality between them. This is probably taken for granted and no revelation, but I thought to make it clear in case there would be any question over this point. To gain more insight into the particular openings comprising the repertoires I refer you specifically to the pdf and Chessable links below.
2. This one is more subjective and a function of the reader's expectations. It has to do with the difference in approach, the style, taken by the authors in their presentations (this can be better appreciated by comparing the respective pdf book excerpts provided below). I believe most would tend to agree that Sielecki's explanation-style is more 'conversational' than Burgess'. In my view this allows for the various themes and plans to be more explicitly and clearly communicated, which I feel is the case with Sielecki. Burgess, on the other hand, relies on providing multiple alternative lines comprised mostly of strings of chess notation for each of the recommended moves, with typically less conversational explanation than is provided by Sielecki. Again, I cannot say which is necessarily the better approach. Some readers may appreciate one approach more than the other.
3. The number of pages devoted by the authors to their respective repertoires is vastly different. Sielecki's White repertoire in "Keep It Simple 1.e4" (KIS 1.e4) is presented in 368 pages. Contrast that with the Graham Burgess' White repertoire which is presented in 73 pages (pp. 116-189), and 68 pages (pp.11-79) for Burgess' Black repertoire (the total page count of the book is 192 pages). Silecki's "Keep It Simple For Black" (KISFB) book is 360 pages. So it appears that on the basis of total page count, Sielecki's books provide more coverage - although the word count density per page in Burgess's book is higher than in Silecki's book (but not by the roughly 5x page count ratio advantage of Silecki's book over Burgess' book). Of course, whether this is meaningful or important is, again, a personal judgement.
4. KIS 1.e4 contains thirty complete, annotated instructional games. IPCOR has none, but does cite relevant games (i.e., players-event-date only) throughout the text which serve to illustrate the specific positions under discussion.
5. Finally, all three of Sielecki's opening repertoire books are available as Chessable courses (including KISFB). However, Burgess' openings repertoire (IPCOR) is not available on Chessable.
The following marketing material and pdf book excerpts should help to provide some additional insight into the content and style of these books...
https://www.chessable.com/chess-openings/s/keep%20it%20simple
https://www.chessable.com/keep-it-simple-1-e4/course/10179/
https://www.chessable.com/keep-it-simple-for-black/course/92793/
Some insight into the books is can be found on the publishers' websites...
Sielecki - KIS 1.e4...
https://www.newinchess.com/keep-it-simple-1-e4-digital-editions
https://www.newinchess.com/media/wysiwyg/product_pdf/9068.pdf
Sielecki - KIS 1.d4...
https://www.newinchess.com/keep-it-simple-1-d4
https://www.newinchess.com/media/wysiwyg/product_pdf/9084.pdf
As mentioned earlier, Sielecki's KISFB book does not seem to be available yet in a print edition in USA (Amazon USA indicates that they will offer it in November 2022), and there seems to be no information on that book on the publisher's (NIC) website (that I could find). However, as mentioned, the book is available as a Chessable course...
https://www.chessable.com/keep-it-simple-for-black/course/92793/
https://www.amazon.com/Keep-Simple-Black-Straightforward-Repertoire/dp/9493257517/ref=sr_1_1?crid=1KH3TAPAQMWJH&keywords=keep+it+simple+for+black+chess&qid=1664444043&qu=eyJxc2MiOiIwLjg2IiwicXNhIjoiMC4wMCIsInFzcCI6IjAuMDAifQ%3D%3D&s=books&sprefix=keep+it+simple+for+b%2Cstripbooks%2C143&sr=1-1
Burgess - IPCOR...
Chessable does not have a course on Burgess' IPCOR.
http://www.gambitbooks.com/books/An_Idiot-Proof_Chess_Opening_Repertoire.html
http://www.gambitbooks.com/pdfs/An_Idiot-Proof_Chess_Opening_Repertoire.pdf
https://www.amazon.com/Idiot-Proof-Chess-Opening-Repertoire/dp/1911465422/ref=sr_1_1?crid=31EJOOVVEI4WG&keywords=an+idiot+proof+chess+opening+repertoire&qid=1664447877&qu=eyJxc2MiOiIwLjg3IiwicXNhIjoiMC41OSIsInFzcCI6IjAuOTIifQ%3D%3D&s=books&sprefix=an+idiot+proo%2Cstripbooks%2C145&sr=1-

Thanks! Yeah, I think the one-volume makes me think it would be very skeletal, but glad to hear you got good use out of it.
@RussBell,
Thank you! It is funny how your breakdown went through the issues I have been wondering about. Sielecki’s books have a more laid back feel whereas the Gambit books are densely packed. Sielecki’s book is also on Chessable, though I am not so keen on the rote training of Chessable.
I was also wondering what any other pros and cons there may be for each of these repertoires, realizing that both of them claim to be “simple.”
Is one better for overall long-term chess learning (e.g., higher likelihood of exposure to a variety of pawn structures over time)? Is one easier to learn and play with less memorization which both authors claim? Is one more comprehensive in terms of early move deviations out of book (breadth more than depth)? What other things should a player consider (besides the author’s writing style) before picking one of these repertoires and sticking to it for a few years?

@dannyhume -
Well, I've done all I can do for you at this time regarding your additional questions without engaging in additional, time-consuming research and analysis, which I doubt you are prepared to pay me to do.
If I had to choose one book over the other - Burgess vs Sielecki - I would have to choose Sielecki's book(s). But fortunately, i don't have to make that choice as I own, or will own, all of the books (Sielecki's KISFB being currently on pre-order with Amazon USA, for November 2022 delivery).
I do agree with you about Chessable's training which consists mostly of presenting the student with lines of chess moves to be memorized by rote repetition, with in most cases little-to-no discussion or explanation of the reasoning behind why moves are made, and virtually nothing describing overall plans and strategies. It's essentially a "monkey see, monkey do" teaching method. Of course, most of these issues appear to be left up to the discretion of the author which means that what you are getting in these regards from any random course is an inconsistent, hit or miss proposition, depending on how industrious or lazy the author is.
To me, Sielecki's books do a relatively decent job of explaining the whys and wherefores.
Good luck to you Danny!


Danny -
I wasn't prepared for that reply!
Actually, as I am retired, have been so for quite a while, and thoroughly enjoying that life, there is almost no amount of money that could entice me! In any case, your money would probably be better spent by purchasing all of the books in question, when you could answer all of your questions yourself (for cheaper)!
Sorry..

I must have at least about a dozen opening repertoire books that promise to simplify your life as either White or Black. Though you may find some interesting things in these books, I don't really recommend this approach, especially for beginners or low-rated players. This approach limits the student's growth of understanding of chess in general and of anything outside the bounds of the repertoire. For lower-rated/beginners, I recommend opening with 1.e4 or 1.d4 and to answer these with 1...e5 or 1...d5. There are no really good shortcuts to learning how to be a better player.

Thanks for the insight. I haven’t much time to invest in a classical repertoire, though that is what I want in an ideal world.
I thought about a comprehensive classical repertoire in as few books as possible that claim to teach ideas, themes, and plans and had come up with the following …
White repertoire:
-Keep It Simple 1.e4 by C. Sielecki
Black repertoire:
-A Complete Opening Repertoire for Black after 1.e4 e5 by Y. Krykun
-Countering the Queen’s Gambit by M. Prusikin (newer)
But still, 3 books is still around 1000 pages, which is too many for someone with little time, yet simultaneously too little to give the respect needed to the universe of classical chess.
Would it not be better to read a single book of 200 pages (Idiot-Proof book) or 2 books that total 700 pages (Keep It Simple 1.e4 + Keep It Simple for Black) that more thoroughly cover a simpler repertoire, even at the cost of a weaker repertoire, if it:
1) gets you back to playing OTB chess; and
2) the time you save compared to the larger repertoire goes to more fundamental skills training such as tactics?

Honestly, my only objection with Keep It Simple (the parts of I have read seem very good) is that his version of “classical” excludes the real “learning” openings like the Open Sicilian and Nc3 or Nd2 French. His Black repertoire Caro-Kann (CK) and QGD with early …a5 is more reputable, but the QGD with …a5 is not the standard mainlines that are recommended for general instruction, and the CK is obviously not 1…e5, though obviously has a strong reputation.
If one wants the shortest path through the fewest number of repertoire books to a comprehensive opening repertoire that plays the types of lines recommended by IM Toth,, these books might be:
White repertoire:
-Starting Out 1.e4 by Neil McDonald (older, smaller, sparser coverage, and not available in Forward Chess)
—or—
-John Shaw’s 3-volumes (if you want more modern)
Black repertoire:
-Krykun’s book (against 1.e4) and
-Prusikin’s book (against the rest).
The larger point I am trying to make is if I am going to go full on classical to supplement my long-term learning, I’d want it all (Open Games, Scotch or Ruy, Open Sicilian, etc), but I don’t have the time.
If I am to cut corners to save time, reduce time on openings (currently I spend none), but still have something to encourage me to play real OTB games (which has its own benefits in terms of thinking, planning, seeing one’s real blind spots when stakes are higher, etc), then the three books in the title of this thread seem to be the leading options.
-An Idiot-Proof Chess Opening Repertoire by FM Graham Burgess (covers White and Black repertoires in 1 densely-packed volume)
-Keep It Simple 1.e4; in combination with -Keep It Simple For Black, both by IM Christof Sielecki (2 books comprising a complete but simple repertoire for the club player)
I have read just about every review of these books that I can find, but have not found a review that directly compares these books to each other, which is surprising to me, since the goals and intended audiences for all of these books seems the same.