Written By will join a select group of two-year-olds if successful in the Blue Diamond Stakes at Caulfield.

The Grahame Begg-trained colt will attempt to emulate the feats of Sepoy (2011), Bel Esprit (2002), Let's Get Physical (1985) and Rancher (1982) to win the colts and geldings Blue Diamond Prelude/Blue Diamond double.

All four have subsequently had stud careers with Bel Esprit siring champion mare Black Caviar.

Written By enters Saturday's $1.5 million Group One feature undefeated after a debut win at Sandown before undergoing an arduous week leading up to the Blue Diamond Prelude on February 10.

Against his normal routine, Begg was forced to trial Written By at Cranbourne to gain a barrier certificate after he proved difficult to load in the gates on debut.

It wasn't until Thursday following his Caulfield win that Begg gave the green light for him to tackle the Diamond.

"He was always going to run if he had a good week after the Prelude," Begg said.

Written By lost 12kg after the Prelude but with time in the paddock and an easy five days had regained that and more and his trainer said he had blossomed since.

"The horse is very resilient," Begg said.

"He had a hard run and he had a hard trial too which made it like two runs in a week.

"He hasn't left an oat since he raced and he's certainly gone ahead."

Begg isn't concerned with barrier 18, which will be 14 if the emergencies don't gain a start, with Caulfield having a straight run from the 1200m start and only one turn.

While his victories to date have come in smaller fields, including 13 when successful in the Prelude, Written By has drawn the outside gate on both occasions.

"He's proven both times he's won that he likes a bit of galloping room," Begg said.

"It depends on how hard a run he gets. If he can get some cover then he can blend into the race when he wants to.

"And importantly he can tough it out."

Written By has remained steady at $10 since Tuesday's barrier draw.

Unbeaten Lindsay Park colt Long Leaf is the $6.50 favourite from Oohood ($7.50) in what is considered the most open Blue Diamond in years.

"He's won two from two, he's in good shape and I couldn't be happier following a nice gallop at Pinecliff during the week," Begg said.

"Put it this way, I wouldn't be swapping him for anything other horse in the race."