Both boxers are so good that they both have to mix it up to keep the opponent guessing. The match will go thru several phases with them trying different approaches. Mostly war mixed up with tactical phases
After an even first couple of rounds of jabbing and feignting, Calzaghe will open up a bit towards the end of the 3rd, landed the best punches so far. Joe will be up by 1 round. In the 4th and 5th, Joe will look to land some meaningful stuff but will get picked off a bit. Kessler up by 1 after 5. In the mid rounds, Joe will start to take over again and realising that Kessler's power isn't all that, will take more risks ad open up his strong combos. This will continue until an onslaught in the 10th where the ref will step in with Kessler protesting that he can go on. So a bit of both, but the "toe to toe war" will only involve one boxer punching. After 6 months of long and hard thought, I can nail it down this precisely.
Both will work hard. They can maintain an impressive workrate over 12. Kessler is not as dynamic as Calzaghe but he is a master at what he does. Joe is a versatile fighter who can box beautifully, tussle on the inside, work off the ropes or go forward and lead. However when Joe leads he is not in his comfort zone. If you check his record that is the only time he really loses rounds. When akward fighters lure him out of his comfort zone i.e. Reid, Bika, Woodhall. They are good fighters and he still wins clearly but he doesn't amaze like he can. This fight will be won in the mind. The more intelligent and strategic fighter will win. It'll be fast paced chess. Calzaghe in terms of skill has more tools at his disposal. Look for Joe to get the decision.