Recently there has been much debate over what Flurry of Blows can and can not do and whether or not it is Two Weapon Fighting.
Lets begin with any non monk class character with TWF feats that has 7 attacks granted to the character wielding a sword in the primary attack hand and a dagger in the Secondary attack hand.
The attack options are four attacks with the Primary hand and Three Attacks with the Secondary hand. For this character then the options are as follows:
Primary Attack four times with the Sword or four times with an unarmed attack (fist) and Secondarry Attack three times with the Dagger or three times with an unarmed attack (fist).
Now give the same set to the Monk with Sword, Dagger and Flurry of Blows with seven attacks the Options are as follows:
Primary attack four times with Sword and none with Unarmed Strike
Primary attack three times with Sword and one whith Unarmed Strike
Primary attack two times with Sword and two with Unarmed Strike
Primary attack one time with Sword and three with Unarmed Strike
Primary attack none with Sword and four times with Unarmed Strike
Secondary attack three times with Dagger and none with Unarmed Strike
Secondary attack two times with Dagger and one with Unarmed Strike
Secondary attack one time with Dagger and two with unarmed Strike
Secondary attack none with Dagger and three with Unarmed Strike
From the above examples Flurry allows the Monk to use weapon and non weapon attacks in combination within the Primary and Seconday attack chains. While two weapon fighting limits the Attack as either with the weapon or unarmed for the attack chains.
If this is how the Devs wanted the Flurry to work than Flurry with a Single Armed weapon is not possible for all attacks. At best the Flurry can yield all primary attacks with a single armed weapon.
Granted two exceptions are permissable for the Monk:
All Flurry attacks are unarmed Strikes.
All Flurry Attacks are with the Shuriken provided the monk has enough ammo available.
This explains the wording of " as if using two weapon fighting feat" and clarifies the " attack in any combination" use in the corebook.
If I am completely wrong about how TWF and how FoB is supposed to work then please post and help me to see what the errors are.
Mathematically they work the same, but FoB does not allow you to qualify for feat that have TWF as a prerequisites.
Right now you have to use two weapons when using FoB. Unarmed strikes counts as more than one weapon however.
This option you gave is not possible at the moment, because it is only using one weapon-->Primary attack four times with Sword and none with Unarmed Strike
The ruling is only provisional, the devs are still debating it.
As Concerro says, FoB is not TWF, because you don't get the access to the follow-on feats, and other aspects do not apply either. So even if the ruling is decided on, it's still not that clear exactly what it means for the monk and TWFing in general.
Concerro and Dabbler
You are correct in that Fob does not quailfy for further feats. That is not what I am asking about. I am trying to understand the mechanic of two weapon fighting feat chain as opposed to the Monk's FoB. I think my view point is what the devs had originally intended but I could be wrong.
A monk can use Unarmed strikes in combination with a monk proficient weapon with Flurry of Blows as written on page 57 of the corebook. What is debated: Can the Fob be done with only one melee weapon? My instincts and the examples I gave above seems to indicate that at best a monk can only use half of the flurry with only one melee weapon and the rest with any conbination allowed within the attack chain.
My Appologies if I am not communicating this correctly.
FoB is "effectively" giving you the TWF feats and double slice. You must use two weapons. If you use all unarmed strikes or all shirukens then that is ok since each shiruken and each unarmed strike can be its own weapon.
Ignore where I said-->"This option you gave is not possible at the moment, because it is only using one weapon-->Primary attack four times with Sword and none with Unarmed Strike"
I thought that line was referring to primary and secondary attacks. The way you wrote it is confusing because you have the primary and secondary attack separate so I don't know which two go together.