Type "B" (collapsed knuckle) forms internal "V"-channel to emulate open bridge
This is true. Mike Sigel and Steve Mizerak are two greats known for using this bridge, well before the "Filipino invasion." In fact, Steve Mizerak even used the "index-finger-pressing-down-upon-middle-finger" bridge on a snooker table, in his challenge matches with Steve Davis:
http://youtube.com/watch?v=LDiO5SS3RnI
(What a great long blue, for a pool player on a snooker table, Steve plays at the 3:00 mark!)
Another thing about this style of closed bridge, is that it most closely resembles the open bridge in terms of the internal "V" construction that the cue accurately guides upon. The cue rides on the bony surfaces of the fingers shaped into a "V" channel, rather than an "O"-shaped loop enclosed by the fleshy pads of the fingers that "give" with varying pressure.
The only issue with the "index-finger-pressing-down-upon-middle-finger" bridge is the orientation of the internal "V"-channel. Most folks who try this bridge, form the "V" in such a way that it's laying on its side, like this ">" (for a right-handed player, forming the bridge with the left hand), or this "<" (for a left-handed player, forming the bridge with the right hand). This, of course, causes the natural "rise" of the cue (that occurs when the shaft's increasing taper moves the centerline of the cue as the "V"-channel forces it upwards) to occur to the side, rather than upwards. Many players, like Mike Sigel, thus orient the bridge hand such that the internal "V"-channel faces upwards, rather than to the side. In Mike's case, he just lifts his palm up off the table, and uses only the middle and pinkie fingers to support the bridge on the table (Mike usually folds the ring finger underneath, or else taps his ring finger on the table as he's thinking, sort of tapping out Morse Code
).
There's a good thread about this, with pictures, here:
http://forums.azbilliards.com/showthread.php?p=3119239#post3119239
Hope this is helpful!
-Sean
I use style "B", way before pinoys were even playing pool over here in the U.S. Mike Sigel and many others from days past use this style.
This is true. Mike Sigel and Steve Mizerak are two greats known for using this bridge, well before the "Filipino invasion." In fact, Steve Mizerak even used the "index-finger-pressing-down-upon-middle-finger" bridge on a snooker table, in his challenge matches with Steve Davis:
http://youtube.com/watch?v=LDiO5SS3RnI
(What a great long blue, for a pool player on a snooker table, Steve plays at the 3:00 mark!)
Another thing about this style of closed bridge, is that it most closely resembles the open bridge in terms of the internal "V" construction that the cue accurately guides upon. The cue rides on the bony surfaces of the fingers shaped into a "V" channel, rather than an "O"-shaped loop enclosed by the fleshy pads of the fingers that "give" with varying pressure.
The only issue with the "index-finger-pressing-down-upon-middle-finger" bridge is the orientation of the internal "V"-channel. Most folks who try this bridge, form the "V" in such a way that it's laying on its side, like this ">" (for a right-handed player, forming the bridge with the left hand), or this "<" (for a left-handed player, forming the bridge with the right hand). This, of course, causes the natural "rise" of the cue (that occurs when the shaft's increasing taper moves the centerline of the cue as the "V"-channel forces it upwards) to occur to the side, rather than upwards. Many players, like Mike Sigel, thus orient the bridge hand such that the internal "V"-channel faces upwards, rather than to the side. In Mike's case, he just lifts his palm up off the table, and uses only the middle and pinkie fingers to support the bridge on the table (Mike usually folds the ring finger underneath, or else taps his ring finger on the table as he's thinking, sort of tapping out Morse Code

There's a good thread about this, with pictures, here:
http://forums.azbilliards.com/showthread.php?p=3119239#post3119239
Hope this is helpful!
-Sean