Well this sure is a weird one.  It has no less than TWO CPUs and
TWO VFDs!  The two VFDs are wired up such as their grids are connected
together so it can be imagined it's a single VFD, and indeed this is
how I have pinned it out and labelled it.

Both CPUs are a very strange Rockwell MM78 series part.  Even though
it is esoteric, there's a good data sheet on it, so I used this to
figure out how it works.

U1 (master) and U2 (slave) are both the same CPU, but with different
mask ROM code of course.

U1 generates the clock using the internal oscillator, and its BP clock
output is fed into U2's clockin.  This way both CPUs are synchronized.

The built in oscillator appears to be around 80KHz according to the
data sheet.  I measured it at around 79.8KHz so 80KHz it is.

The two CPUs are connected together with 5 signals-  This CPU has a
built in SPI style serial bus, so these are cross-wired (CLK is
connected to CLK, and SDO is connected to SDI and vice-versa).  
There's also two other control signals that are cross-wired between
the two chips.

The PCB on this game is the shittiest quality one I have seen in awhile
with lifting foils and no silk screen at all.  They seem to have used
chip pins as passthroughs to get routes from one side of the chip to
the other instead of trying to squeeze them in between pads.  I have
labelled these as "(passthru)".  Some of them I am not too sure of
if this is the case or not, so I put a question mark after it.  I am
fairly sure this is right, though, because the route would not continue
through the pin to another farther on if this wasn't true.  (Well... 
usually).  It's possible they are using the interrupt inputs though
and the lines are bidirectional, but I don't know.  To be safe they
can be connected during emulation as shown.

From first blush it might look like I left 10 buttons out of the matrix
but I really haven't.  The game's four(!) directional pads w/ center
button are duplicates.  The two visitor d-pad+center buttons are wired
up in parallel, and so are the two home ones.

I think the theory was you could make plays behind the little flip 
up door using the top set so your opponent couldn't see your plays,
but you could use the bottom D pad for normal play when it didn't
matter what play(s) you were setting up.