well, what's wrong with 3-5 and 4-5?

They are less flexible. They force you to decide/declare your intentions sooner.

well, what's wrong with 3-5 and 4-5?

Pros do not play them because they do not win. We amateurs are under no such restriction, so enjoy!

Here is a quick table based on GoGoD (still summer 2012). This summarizes the first play in the 4 empty 10x10 quadrants of a little over 25,000 even games since 2002 (roughly the 6.5 point komi era). The plays are listed by frequency except for the top two lines (because I made a mistake )

What it tells us is (for example looking at the first two lines):
Black played first move on 3-4 a little over 31,000 times, winning 49.7% of those games. Meanwhile White played first move on 4-4 a little over 32,500 times, winning 51.4% of those games.

Plays on 3-4 and 4-4 accounted for some 98,000 out of 100,000 corners. Also shown is the difference in winning percentage for other choices compared to the best performer for Black (3-4) and for White (4-4). Note that any single game combines a variety of first plays and that the first play does not, in fact, determine the nature of the joseki played. For example if Black plays on 3-4, a White approach on 5-3 that is ignored by Black may turn the corner into a 5-3 joseki. Such distinctions are completely missing from this analysis. As always YMMV.

Pros do not play them because they do not win. We amateurs are under no such restriction, so enjoy!

Here is a quick table based on GoGoD (still summer 2012). This summarizes the first play in the 4 empty 10x10 quadrants of a little over 25,000 even games since 2002 (roughly the 6.5 point komi era). The plays are listed by frequency except for the top two lines (because I made a mistake )

What it tells us is (for example looking at the first two lines):
Black played first move on 3-4 a little over 31,000 times, winning 49.7% of those games. Meanwhile White played first move on 4-4 a little over 32,500 times, winning 51.4% of those games.

Plays on 3-4 and 4-4 accounted for some 98,000 out of 100,000 corners. Also shown is the difference in winning percentage for other choices compared to the best performer for Black (3-4) and for White (4-4). Note that any single game combines a variety of first plays and that the first play does not, in fact, determine the nature of the joseki played. For example if Black plays on 3-4, a White approach on 5-3 that is ignored by Black may turn the corner into a 5-3 joseki. Such distinctions are completely missing from this analysis. As always YMMV.

Thank you for the stats, quite interesting.

However, I suspect there's more to the correlation than causation. I think 3-5 and 4-5 also tend to be associated with fighting games and may thus be used more frequently by weaker players who would prefer decide the game on a fight rather than play a calm game and lose by a few points. Therefore the lower winning ratio could reflect this tendency rather than inherent weakness/difficulty to play.

Since, this thread was started, I have had several games against the 3-5, is it really good for fighting?

Dave, your results surprise me in one way: I thought Black's win rate in modern play is greater than 50%. Do you know if that's right, and if so, what makes your results look different?

I don't have a source off hand, but I think I had read somewhere to that after komi went up from 5.5 to 6.5/7.5 it went from black winning slightly more to white winning slightly more.

I have seen it written that under Chinese counting there is no difference between '3.25' and '3.75'. The stats say that there is a difference between '6.5' and '3.75' though!