International powerhouses Coolmore and Godolphin continued to spend freely during the second session of the Keeneland September yearling sale, in pursuit of yearlings by internationally successful sire War Front, to help fuel a robust market at North America's premier yearling auction. Coolmore purchased a $2.4 million War Front colt who became the most expensive yearling sold in North America this year and Godolphin acquired the $1.75 million War Front filly who checked in second at the session as the Claiborne Farm sire led all stallions on the second day of selling. "What can I say about War Front?" Coolmore's M.V. Magnier said. "Over the last couple of years, we've been exceptionally lucky with the horse." War Front had three seven-figure yearlings on the day as eight horses reached that threshold overall. Another 11 yearlings sold for $750,000 or more in a robust marketplace. "Very strong - I knew it would be," noted bloodstock agent Mike Ryan said of Tuesday's session. "It always is, deeper in the sale, it's always stronger the second day, and probably the way the book fell, there were some stronger horses today. The good ones, people are there today." Tuesday's session finished with 168 yearlings sold for total gross receipts of $65,835,000, resulting in an average price of $391,875 and a median of $300,000. Keeneland revised the format of the September sale this year, expanding the marquee Book 1 portion from a single session with 167 horses in the catalog to four sessions totaling 989 yearlings to open this sale. With the change, session-to-session figures, particularly for gross sales, are not applicable for market comparison. Last year's narrow Book 1 - which finished with an average price of $570,263 and median of $500,000 - was followed by three Book 2 sessions. Thus, this year's four-session, expanded Book 1 effectively serves as a blended Book 1 and 2, in terms of quality. That portion of the 2017 auction posted a cumulative average of $288,759 and median of $200,000. The buyback rate for Tuesday's session finished at 21 percent - a very low figure for a selective marketplace, and an improvement compared to 35 percent on Monday. "It was competitive at the top, it was competitive at the middle, and it was competitive in the bottom," Bob Elliston, Keeneland's vice president of racing and sales, said. "There was lots and lots of business getting done at every level today. We were cautiously optimistic that [the market] was strong, but I cannot sit here and tell you we thought it would be as strong as it was today." The buybacks did include an extremely high-profile yearling, as a Will Take Charge colt who is a half brother to undefeated Triple Crown winner Justify went home to Glennwood Farm with a high bid of $1.75 million. Glennwood's Tanya Gunther, who says the family operation will break the colt on the farm this fall with an eye to racing him, attributed the result to the colt's unproven sire. Will Take Charge has his first 2-year-olds on the track now, with three winners from 15 starters. "I think mostly the stallion being unproven, it's a little bit tricky," Gunther said. "Nobody really thought Will Take Charge was going to come out with August 2-year-olds, so it is as expected, I think, right now, but still the market waits to find out what he's going to do." Meanwhile, the War Front colt who led the session will head to Ireland and will be trained by Aidan O'Brien at Ballydoyle for Coolmore, Magnier said. The colt is the second foal out of the Grade 1-winning Smart Strike mare Streaming, a full sister to stakes winner Treasuring and a half sister to stakes winner Cascading and stakes-placed Distracting and Gifting. Another sibling, Achieving, is the dam of Group 1-placed stakes winner Arabian Hope and stakes winner Counterforce. Streaming's granddam is blue hen Better Than Honour, the dam of Kentucky Oaks and Belmont Stakes winner Rags to Riches, fellow Belmont Stakes winner Jazil, Breeders' Cup Marathon winner Man of Iron, and Grade 2 winner Casino Drive. "It's our best pedigree, and I've very proud of the fillies we've developed over time," John Sikura of consignor Hill 'n' Dale Sales Agency said. "We've retained fillies and offered these good colts, so we hope they are hugely successful with the horse. War Front is "a world-class sire, so that's very important," Sikura said. "[This colt is] a great physical horse. He has a lot more length and stride than a lot of War Fronts. He wasn't the Northern Dancer type, he was more the Nijinsky type. Big frame, still immature, great limbs, lots of bone ... really smooth mover, great disposition, and really, a presence about him." Earlier in the day, Godolphin went to $1.75 million for a War Front filly who is a half sister to 2016 Kentucky Derby winner and 2015 Eclipse Award champion juvenile Nyquist, from the consignment of Hinkle Farm. They are both out of the winning Forestry mare Seeking Gabrielle, a half sister to four stakes horses, including Grade 3 winner Seeking the Sky, dam of Grade 1 winner Sahara Sky. "Very strong [market], but when you're buying a filly of that absolute quality, from a fine breeder, by a great stallion, half sister to a Kentucky Derby winner, that's exactly what you expect to pay to race them to be a broodmare," said John Gosden, who signed the sale ticket. Godolphin, which finished as the day's leading buyer by gross, also purchased a $1.3 million Curlin colt from the consignment of Eaton Sales. The colt is out of the stakes-winning Flatter mare Stoweshoe, a full sister to Grade 1 winner Taris and a half sister to stakes winner Theatre Star. War Front's other high-ticket offering was a colt out of the stakes-placed Lookin At Lucky mare Pin Up who sold for $1.2 million to Shadwell Farm from the consignment of Dromoland Farm, as agent. It is the family of Irish 1000 Guineas winners Quarter Moon and Yesterday. Fueled by that trio, War Front finished as the session's leading sire by both gross and average, with the latter finishing at a staggering $1,046,250 for eight yearlings sold. Triple Crown winner American Pharoah, his sire Pioneerof the Nile, and his grandsire Empire Maker were all represented by seven-figure lots on the day. Coolmore continued an active day as it went to $1.2 million for an American Pharoah filly. She is half-sister to Grade 1 winner Cupid, Grade 3 winners Heart Ashley and Ashley's Kitty and stakes winner Indianapolis, and became the seventh seven-figure sale from her sire's blockbuster first crop. Coolmore stands both American Pharoah and Cupid, who entered stud this year. Keeping things even more in the family, the filly was consigned by VanMeter-Gentry sales, whose Tom VanMeter delivered American Pharoah in February 2012. Magnier said that the filly was another who would ship to Ballydoyle. Although American Pharoah never raced on the turf, Pioneerof the Nile won his maiden on turf and won the Grade 1 CashCall Futurity on synthetic, and is the sire of turf performers such as Grade 1 winner Midnight Storm. "I remember when Bob Baffert was [training him], he said that he really thought that American Pharoah would have went on the grass," Magnier said. Albaugh Family Stables and Spendthrift Farm continued to build their partnership as they went to $1 million for a Pioneerof the Nile colt. Spendthrift stands the Albaughs' multiple Grade 1 winner Brody's Cause, and will stand their Grade 1 winner Free Drop Billy at the conclusion of his career. Consigned by Brookdale Sales as agent for Hardacre Farm, the Pioneerof the Nile colt is out of multiple Grade 2 winner Pomeroys Pistol. A colt from the return crop of Empire Maker, who was repatriated for the 2016 breeding season after several years in Japan, sold for $1.35 million to Phoenix Thoroughbreds and will go to Bob Baffert, who trained American Pharoah, Pioneerof the Nile, and Empire Maker's other classic-producing son Bodemeister. Consigned by VanMeter-Gentry Sales, as agent, this colt is a half brother to graded stakes winner Conquest Big E. A $1.4 million colt by young classic sire Uncle Mo was purchased by Ryan on behalf of a partnership. Ryan, who said, "We're dreaming Derby," scouted out Nyquist, the star of Uncle Mo's record-setting first crop. "I thought he was very, very special," Ryan said of Tuesday's purchase. "He blew me away when I saw him, because he reminded me of Nyquist. This horse was very, very special. ... Might have been the best yearling I saw this year." The colt, consigned by Bridie Harrison as agent for Peter J. Blum Thoroughbreds, is out of the placed Street Cry mare Secret, from the family of Grade 1 winner Well Chosen. For hip-by-hip results from Keeneland September, click here. -- Additional reporting by Matt Hegarty