The topic is too broad. There are many good black replies to Réti: 1...c5, 1...d5, 1...e6, 1...Nf6 and others.
RETI OPENING


i like the reti and especially transposing to a london. im still just a baby patzer but i will say my rating has increased since playing the reti with londonish principles. i like the postional and tactical aspects and flexibility. the hypermodern style is really dynamic and i really think that the reti and london will fit me well.

The topic is too broad. There are many good black replies to Réti: 1...c5, 1...d5, 1...e6, 1...Nf6 and others.
I switched to using the Reti as a primary opening about a year ago (used to play 1. e4 without fail). It is a hypermodern opening, but more than that it really is an opening which evokes the types of kill-or-be-killed games Richard Reti was famous for. Often times, it will lead to a wild series of exchanges across the center, and even when it doesn't pan out in your favor, there is always counterplay.
The book reply 1. ..d5 is most common, but you need to be prepared for 1. ..c5 and 1. ..Nf6, as well. I try to avoid transposing to Queen's Gambit openings, which is common both on the main line and with 1. ..Nf6 (I recommend playing 2.g3 in response to this). Also, it takes a bit of positional understanding on the main line to know why 1. Nf3 d5 2. c4 d4?! (3. e3 to follow) is good for white.
But most basically, in order to deploy the Reti Opening effectively, you need to be comfortable with unbalanced, high-tension positions. It is a weapon for tactical, aggressive players, but it also requires precise and active defense.

Possibly of interest:
Starting Out: The Reti by GM Neil McDonald (2010)
https://web.archive.org/web/20140627101228/http://www.chesscafe.com/text/hansen131.pdf
http://www.jeremysilman.com/shop/pc/Starting-Out-The-Reti-76p3799.htm
Dynamic Reti by GM Davies
https://web.archive.org/web/20140627005248/http://www.chesscafe.com/text/hansen64.pdf
The Modernized Reti
https://www.newinchess.com/media/wysiwyg/product_pdf/7780.pdf
Hi, this forum is all about Reti... Write here everything with Reti... I would also like to learn good Reti to play
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