Here’s a Cliburn competition challenge for you: Guess which piece of solo piano music will be heard most often during the 17-day event.The 30 pianists going for the gold in the Cliburn will each play two 45-minute solo recitals in the preliminary round. Twelve of those competitors will move on to the semifinal round, where they will be required to play a 60-minute solo recital and give a chamber music performance. Then the six finalists will conclude the competition with performances of one small and one large concerto with orchestra.And they have to make all of their programming choices before the competition. Mid-event changes are not allowed.Those solo recitals can include a couple of long works, or several shorter pieces. But, any way you cut it, Cliburn audiences will hear dozens and dozens of solo keyboard works — including several that will be heard more than once.So, what is the favorite piece of the virtuosos who will be putting their mettles to their keyboard pedals at Bass Hall in the coming days? Go ahead. Take a stab at it. (But we bet you are going to be surprised by the answer.)You are probably going to start with the instrument’s greatest composers, like Frederic Chopin. And what a likely suspect. His works are always popular at the Cliburn, and we could hear as many as 25 of his solo works at this competition. His 24 Preludes, Op. 28, is scheduled to be performed up to four times (twice in the prelims and possibly twice in the semis, depending on who advances).But, impressive though that is, it does not come close to being the most common piece.So, if not Chopin, Liszt, you say. The pianists at the Cliburn love Liszt because he composed so many notorious knuckle-busters that allow them to show how fast and loud they can play. A typical page of Liszt sheet music looks like a Mozart sonata that has had a grenade dropped on it. So it is no surprise that about 28 works by Liszt (if you include his transcriptions of other composers’ works) are among those planned by the Cliburn competitors. His daunting Sonata in B Minor (which is more darkly introspective than bombastic) is scheduled to be heard four times (three times in the prelims and once in the semis).So, again, a good choice for your guess, but a wrong one. It has to be Rachmaninoff, right? His lushly Romantic heartstring-tuggers (which sometimes feature bits of 20th-century pyrotechnics) always please the crowd and often impress the judges. So it is little wonder that 17 of his solo works are listed by the competitors. But, of those 17, only two ( Variations on a Theme of Corelli, Op. 42, and the Sonata No. 2 in B-flat minor, Op. 36) have the potential to be heard twice.Didn’t remember Schumann, did you? He not only composed some of the greatest piano music of the early Romantic era, he also married one of the greatest pianists of his time, Clara Wieck Schumann. The Cliburn pianists certainly didn’t overlook him. They programmed 15 of his works. And his roiling and impassioned Fantasie in C major, Op. 17, could be played a whopping seven times (definitely four in the prelims, up to three in the semis). Surely no piece will be heard more often.But even galloping at that pace, in this particular horse race, Schumann is no shoo-in.Now you are running out of viable options and are trying to remember the pieces that became etched in your brain like bubblegum pop hits at past Cliburns.Mussorgsky’s massive Pictures at an Exhibition? In past competitions, it seemed to be the choice of every other player, but we will hear it only once or twice this time around (depending on if a certain player makes it to the semis).Busoni’s brilliant transcription of the Chaconne from Bach’s Violin Partita No. 2 in D minor? That piece, played so frequently in previous Cliburns, will not be heard at all this summer, more’s the pity.You are probably out of composers by now, without getting close to guessing Stravinsky as the man behind the work most frequently selected by the competing pianists. They have programmed his Trois mouvements de Petrouchka (Three Movements from Petrushka) eight times. And since five of those eight listings fall in the preliminary rounds, that means we will almost certainly hear that work more than other solo pieces (except for the competition’s new, commissioned work, which will be played by all 12 semifinalists).Stravinsky, who was much better known for his orchestral than solo keyboard works, composed this 14-minute piece in 1921, 10 years after he created the popular ballet on which it is based. The three parts of Trois mouvements are I. Danse russe, II. Chez Petrouchka and III. La semaine grasse. It makes a great showcase for the Cliburn pianists because the first section is light and playful; the second is modern, angular and a bit abstract; and the third (which is more than twice as long as either of the first two parts) falls somewhere between, displaying a wide range of personalities.The piece was composed for legendary pianist Arthur Rubinstein, who played it numerous times but, interestingly, never recorded it. The level of difficulty of this work is evidenced by the fact that, biographers point out, Stravinsky, who frequently performed at the keyboard, was not enough of a virtuoso to play this work himself.But, obviously, it is not beyond the reach of the ivory merchants planning to hammer away at the classics in the days ahead. It just goes to show that, in any piano competition, you can’t count the Russians out.Large concertos and string quartetsWe won’t know which concertos we will be hearing in the competition’s final round until we see which six finalists make it.But we do know what they all plan to play, and it seems likely that we are, once again, about to be drowned in the shimmering, Romantic sea that is the Rachmaninoff Piano Concerto No. 3. Eight competitors have selected that work for their large concerto, should they make it that far. So that means, in theory, we could hear only that piece in the competition’s big concerto round.In addition, two players have chosen Rachmaninoff’s Piano Concerto No. 2, and two others have selected his Variations on a Theme of Paganini. So Rachmaninoff seems likely to make the finals. But we could hear from some other composers. The rest of the field breaks down like this:• Tchaikovsky Piano Concerto No. 1: programmed by five contestants.• Beethoven Piano Concerto No. 5: programmed by five contestants.• Prokofiev Piano Concerto No. 2: programmed by five contestants.• Prokofiev Piano Concerto No. 3: programmed by three contestants.Dvorak was the overwhelming favorite among the four choices available in the piano quintet round, in which each of the 12 semifinalists will perform with the Brentano String Quartet.A dozen pianists chose his piano quintet, while nine plan on Brahms, six are going with Schumann, and three prefer Franck. Sources: The Cliburn, “The New Grove Dictionary of Music and Musicians, Stravinsky” by Neil Wenborn, “The Great Pianists” by Harold C. Schonberg, “Classical Composers” by Peter Gammond, various CD booklets.