http://www.youtube.com/watch?v=ut2mZKIGJgQAlthough we only got to see 2 of his matches, we can see the technique he saved for the tournament specifically, which are several new variations of Sion resets that lead to high damage opportunities.
It looks like the secret to this technique involves using the basic cutting synch loop into 5[C] 214B. From here you have multiple options that can allow you to reset the combo damage, go into heat activation, or just finish the combo.
The 'trigger' is 5B. Here are the options Kubo uses, as well as what I have mapped as the full set of techniques I believe he was prepared to use.
1:15: 5[C] 214B 5B 2B 5C(1hit)5A (combo is now reset) 2C 421A. In this case the 2C was successfully blocked but gave Kubo an easy sudden throw setup for the win. On hit the 2C 421A leads into the double otg combo, or otg into TK j.214C for easy 3k damage.
2:09: 5[C] 214B 5B 2B 5C 214A immediate heat activate. This is actually an old setup, but worth noting here because it is probably what gave him the ideas for the other options.
9:35 5[C] 214B 5B (in between here the combo is now reset) 6B 2B 3B xx 421C. This is a variation of an older setup modified for his new 'cutting synch reset' theme.
Here is what looks like the full set of options Kubo was prepared to use.
5[C] 214B 5B2B5C (one hit) 6B 3B 421C
5[C] 214B 5B2B5C (one hit) 5A 2C 421A
5[C] 214B 5B2B5C (one hit) 5A Dash up throw
5[C] 214B 5B2B5C (one hit) 214A heat activate
5[C] 214B 5B 6B 2B 3C 421C
5[C] 214B 5B 5A 2C 421A
5[C] 214B 5B 5A Dash 2A
5[C] 214B 5B 5A Dash up Throw
Note that there is another (implied) damage increase once your opponent is aware of these:
He will stop mashing damage after 5[C] 214B because he wants to watch your setup closer and does not want to accidentally get himself counter hit.