tony37 wrote on 03/17/14 at 15:30:12:



of course

the dilworth, like most other 'pet' lines (viable sub variations of main lines inside large opening complex) is only going to be essayed with the cooperation from an opponent

the riga, otoh, can be put on the board more often but is an invitation to have one's teeth pulled without the administration of a proper anesthetic first 

Regarding quick/decisive wins by Black in the Dilworth, I think of two games from the 1980s:  Ljubojevic-Yusupov and Spassky (as White) against the German master Neunhöffer.

The Riga is probably a fine surprise weapon at a certain level, but beyond that I don't know. 

I don't know why the Dilworth should be problematic at all (though I haven't kept up with the theory); it's been considered OK for many years, with strong players taking it up from time to time.  The trouble may come at amateur level when someone might try to play it as an "attack," which is just wrong.  Black often gets balanced endgame positions where his active rook and pawn(s) are an equal match for White's pieces.  Obviously there is new theory to check here, but you should acquaint yourself with the typical endgame plans by looking at some older games as well, i.e. of Yusupov's.  Jonathan Tisdall had a nice little section on this in his wonderful book Improve Your Chess Now.

So I somewhat agree with Brabo that anything from 2002 will be outdated, but just want to remind you to study those typical endgames in addition to whatever new theory has come along.

Edit: in fact I'm very surprised to see White managing a paltry 43.9% score in my database after ...Qxf6 in the Dilworth.  That's just a raw number without any filtering out of weaker players, etc., but still remarkable.  As far as I know, the Dilworth has been considered fine for Black for many years, though as with any other main-line opening ideas come along to test Black and then fade away, etc.

RoleyPoley wrote on 03/17/14 at 00:12:07:


Good for surprise value perhaps, but if you have little study name, it's wasted on knowing the details of how to reach a slightly dubious ending. Knowing how to defend the resulting endings might have some value, if you were going to specialise in it. There's also the practical problem in the Riga of the instant draw by taking the Knight on h2.

I fail to see why I should study the Riga. I could easily get an equally losing position myself, without any study! 

Both Dilworth and Riga have long forcing lines.  They both lack strategic flexibility.  But you might value that quality.  They have one-time surprise value but their effectiveness will drop against repeat opponents once they know what to expect from you.

Seirawan published a Youtube lecture on the Riga variation that prompted this thread:
http://www.chesspub.com/cgi-bin/yabb2/YaBB.pl?num=1372059672

I am not a big expert on the matter, but I think Open Lopez is a fair choice for club players and if you like the Open Lopez in general then it makes sense to dabble in the Dilworth and Riga here and there to see what you think and for variety.

If you don't like the Open Lopez in general, I wouldn't bother with Dilworth or Riga.

Just my opinion.

Reading through Grandmaster Secrets: Openings  by Andy Soltis (2002), he recommends both the Riga and Dilworth variations for black saying they can be learned over a long weekend.

How difficult are they to learn and are they practical openings for a club player?