Scenario 1) Two equally skilled combatants square off against each other to the death, one has one or two katanas (depending on preference), one has two sais, who is going to be the victor?
Scenario 2) You are a skilled combatant in sais and katanas. Which weapon do you choose to dispatch a large quantity of enemies? i.e. Which is going to kill faster?
Sai will win… dual wielding katanas is retarded. Sai are lighter, faster and more nimble.
A single katana may be a different story.
Sai with a skilled combatant can easily parry and block a katana attack. Especially from someone who is dual wielding, who is now crippled by the weight of a single katana blade in each hand.
A single katana will be more devistating in a large onslaught. the sai require close quarters combat, giving the enemy a chance to grab, or tackle you to the ground for his buddies to finish the job. Keeping distance in a numbers fight is crucial to victory.