There are plenty of ways to look at how the Happy Valley Million Challenge might turn out at the end of tonight’s meeting but all the calculations might just be rendered pointless if Danny Shum Chap-shing-trained General Iron wins the Blue Pool Handicap (1,200m).

Five horses, potentially, can win the Happy Valley contest which has run in Class Three and above since September – Speedy Longwah, Divine Boy, General Iron, Fantastic Feeling and Superoi. The clubhouse leader Speedy Longwah is not racing tonight, nor is joint-second Romantic Cash, both of them Shum-trained too. Divine Boy is a point in front of General Iron and runs two races earlier but he has a difficult assignment finding his way back to top form after tackling the Classic Mile in January.

General Iron (Derek Leung Ka-chun), on the other hand, is coming off a booming second last week behind Mr Right over 1,000m, and is set up to add his fourth Happy Valley win to his record.The six-year-old missed a lot of the 2014-15 season with injury and needed some racing at the back end of that season to find his legs again. However, General Iron has held together well and gone to new levels this term, winning twice and only once out of the placings in his other five starts. He sizzled home last week over 1,000m to miss by a half length and will be the hardest to beat if he reproduces that – the question is whether he does as he has never raced on the one week back-up.

The race is no pushover though, with another back-up horse from Sunday, Travel First (Neil Callan) a strong danger and so too Righteous (Zac Purton) and Fantastic Feeling (Ryan Moore).

Travel First was a good thing beaten on Sunday after having a tough run over 1,400m when second and trainer Dennis Yip Chor-hong has avoided any handicap penalty by running him again so soon.