Hi all.  I have an absolutely amazing chess game to show you. It is Stockfish eight playing
with the white pieces against AlphaZero.
It is from TCEC (Top Chess Engine Championship) conditions of TCEC
start position and it's actually shocking. AlphaZero has a total disaster in this
game. It's the shortest ever loss on
record against Stockfish. So what on
earth happened here? Chess is 99% tactics
a chess quote by Richard Teichmann.  So the
neural network approach is not totally
about calculation. It is about learning self
learning and often that's patterns like
"Thorn" pawns
Does it help AlphaZero here? We have e4 from Stockfish
e6.  This is the book moves given so the
French defense territory the classical
variation and encouraging White to
close the center. so Nf6
the classical variation we have Bishop
g5 which is a key move Bishop e7 and now
e5 Nfd7  and now h4 - The Alekhine Chatard Gambit - a very dangerous gambit
now in this game the book move given is
Bishop takes g5 to accept the ferocity
the dynamic aggression of white's pieces
on that h-file. Black has other choices
like c5 in chessbase LiveBook has been
played before or h6 for example h6 we
could take on e7 but this isn't so scary
for black if black's not greedy this
looks like a reasonable position.
White does have a small edge but blacks
got chances to undermine the center as
an example but here the book move given
Bishop takes g5 so the full dynamic
pressure of white is here. After Knight
h3 this is the known 
continuation. Now usually here  ...
Queen g4 was played here prompting
g6 and now usually there's Knight f4 in
this position which has various ideas
but here we have Knight g5 which does
seem a really interesting alternative
as proven by Stockfish. If there was ever
a theoretical novelty in the French
defense this is I believe one of the
most important and touched on it before
in another video actually. Knight g5
seems really dangerous looking at f7 and h7. So here AlphaZero plays h6. Just to
show you some of the dangers already
tactically. Say black plays Nf8
the Queen on g4 is useful for bang
Knight takes d5 and then Queen takes
c8 check.  So there's already little
tactics like that to be aware. The
pawns hit though. That's the key
thing so black can't really do that defending the
pawn. So black plays h6 another pawn move on
c5 yeah if this pin doesn't really help
black because it backfires on the pinner
after Nf6 check and then this is
check. So we have h6. White just ignores
that knight - just leaves the knight on g5
just castles Queenside because of the
pin against h8 so we have knight c6 here
now again on Knight f8 there's the
tactic Knight takes d5 using that pin
against the e6 pawn against the c8
Bishop. So that's not possible. Knight b6
looks plausible but Bishop d3 has the
menacing idea of Knight takes f7 a well
known kind of tactic. For example knight
c6 bang knight takes f7 and if Queen
takes then there is Bishop takes g6 pinning
the Queen to the king and if King takes
this is also bad because of check here. 
And then the rook slides in with rook
h3 and this is devastation. If
black has to give up that rook this
position - even though the bishop is lost
Black is really pinned up here as ending
up losing anyway in this scenario. It's
horrible for black with that pin on the
c8 Bishop against the rook and the
protector of the rook has been taken
away with Na4.  So that's all pretty
devastating stuff so the decision here
was knight c6. So this avoid the possibility
now if c5 undermining the White center. So
the white center is pretty secure here
now. And in fact also Nb5 is
now dangerous. We have two knights on the fifth rank.  Common advice is to try and
kick away a knight when it's on your
fifth rank. Because you know
they're quite tactically dangerous so
here the knights
are really both kept tactically 
dangerous on both sides of the board
There is an aesthetic tactically to this
game. Now here
Knight b6 is played defending c7 like
that. So again let's run with that. Now
an interesting move Rd3 which
this third rank is free to use by both
rooks and a great target here is f7 of
course so this is a great way of
mobilizing to f7 this d1 rook. We have h5
if we look at this position with say a6
then Knight takes f7 is really
dangerous believe it or not. For example
axb5 there's taking the rook. This is
harmless because of King b1 and White
can weather the storm here by protecting.
Make sure c2 is protected after the
checks and then play Rb3 and
then there's always Ra3 knowing
that c2 is protected so this position is
okay. c2 is protected there. It's the
black attack that is repulsed there. The
rebellion is crushed so yeah White's
winning that so a6 Nxf7
is really dangerous so axb5 is not
working. Queen takes there's Rf3
and black falls to pieces here basically
say this Knight takes c7 dragging
the Queen away for Queen takes g6
and although black is material up, black is falling to bits. Qxh8 check for example
there. So this is really devastating
stuff. So we have h5 being played and now
this is just ignored.  Rf3 is played - a
brilliant move tactically just
ignoring that because if the queen is
now taken then the forcing move rook
takes h8 check
and now rook takes f7 regains the queen
with big interest. This is a big
advantage for White.  So casually
ignoring the Queen being attacked and
putting more pressure on f7. The soft
spot. So a6 is played and now here
another fabulous
tactic - Queen g3 is played so
basically there is now the idea of rook
takes f7 so offering the knight on b5.
Now this is immune as well because if axb5
Rxf7 - this is devastation
after c3 for example Queen a4
Queen f4 this is just too much for black
to bear. For example the Queen goes there
then this Knight is pinned making Qe7
checkmate a threat and that's not
good news. But let's have a look at this
again
So if say rook a3 here you might
think. Rook takes c7 the casual rook
takes c7 and taking the Queen this is a
big advantage for white this position
yeah it's it's all pretty crushing this
axb5 doesn't
work after rook takes f7. Black is falling
to bits so we have actually Knight d8
and you can see that the congestion the
cramp
these spectator pieces are not helping
the soft spot. The critical soft spot of
black's position is not helped by these
pieces on the Queen side here. We have
the knight now retreating to c3. Now
Knight d7 is played. On Bishop d7 you
might think to try and do something with
the Queen side pieces. Bishop d3
targeting at the pawn chain. So for
example h4 queen g4 and then bang Nxf7
is devastation. This is too
much
"pin and win" is on a famous tactical
quotation and here it's pretty evident
this pin is crushing. White's gonna be
winning material back. Black has to get
away from there and white has a big
advantage there so we have Nd7 Bishop d3
more pressure on that pawn chain around
the King
Great scrutiny. Nf8 is played
Here if c5 Knight takes f7 rook takes f7
is devastation after Bishop takes g6.
And if King takes here then Queen
takes and then the rook swings in for
that rook f3 for a big advantage for White.
So we have Nf8. Rook h4 and the
rooks are kind of doubled. We say
sometimes to have the pawns ahead of the
pieces but here the pieces are ahead of
the f2 pawn.  And it doesn't really matter
because the idea of doubling rooks works
tactically. If it works it's okay
sometimes as they say. You don't have to
be too theoretical about how one attacks
soft spots. Now here Black
played rook g8 and in this position as
an absolutely stunning tactical move and
in fact btw I had a nice discussion 
on the Leela forums about this move
and saying could could the classic AB
engines find the best move in this
position. Actually they found the testing
move instead of this at some point but
that there was either a testing move
which actually leaves the position
exactly as it is and you can retry to
find this more positive move. If I give
you five seconds to pause the video what would you play here? It's totally breaking the
black position in all variations this
next move. It's absolutely magical
tactically so five seconds to pause the
video. White to play.
Bishop c4 !!. Yeah product of
exhaustive search. Classic alpha
beta engines finding this wonderful move
The move in the forums BTW was
the neutral move Nh3 which basically says
that rook takes Rxh5 is a threat because
it's pinning that pawn now for Rxh5
and you might have your Stockfish
give Nh3 and the rook unpins and
then you have this position again and
the the rook goes there again so you end up having to play a constructive move and
you might find in your analysis by the
way it Stockfish does this all the time
these testing moves which apparently
they don't really do anything anything
negative to your position. But when
you're analyzing games like this you
really want to find the more
constructive moves a lot at the time. So
the constructive move here is this
Bishop c4. Now whatever way
or whatever black does black is in big
trouble here. We can tell intuitively
that there's spectator pieces here on
the Queen side so why is this
devastating? Well Queen d7 was played in
the game. On c6 White can just play
either Knight actually to e4 for example
so threatening that huge Knight f6 check
so for example here and then this
position is really devastating after the
check
winning the rook on g8 so taking there.
And so in fact yeah either Knight could
have popped into e4 there for this
Knight f6 check. So c6 doesn't really
help because of this. Either Knight to e4
dxc4 actually gives the feature of
pawn mobility for white which can be
immediately used with d5 and the big
threat of d6 as well is is something to
be considering here. So for
example Nd7 rook takes c4 as well with
now Rxc7 and d6 on the cards is
absolutely devastation for example like
this.
They're absolutely devastating lines
here. White crashing through basically so
yeah these lines crashing through let's
have a look. And on Bishop d7 there by the
way there's d6 bang which actually is
winning the Queen. The Queen will have to
give herself up for something that's
actually winning the Queen so this is a
totally devastating position after d5
It's fascinating stuff. So this
this position here Rxc4 is
absolutely critical for black so that
makes that work. So let's have a look at
this Bishop c4 again so we've looked at
c6 dxe4 dxc4 say Nd7
We have looked at in the variation Knights d7 here - if so on
Bishop c4 Knight d7 we're saying this
position Bang - Bishop takes d5 Knight
takes d5. Knight takes c7 check that's
falling apart this is devastating.
e6 opening up this diagonal and now
yeah winning the Queen playing the check
this is just absolutely miserable black
couldn't even take there because of Queen d6
checkmate so yeah all of this
devastation happens basically yeah
whatever reply there on Bishop c4
so yeah magical move Bishop c4 magical
tactical move. So Queen d7 was the response from AlphaZero but now Nce4 so leaving
two pieces hanging but wanting to go
to f6 to fork the Queen and King
this is taken Knight takes. Now there's
no Queen takes because again Nf6 check
if Queen takes d4 Knight f6 check
unveils the attack of the rook against
the Queen. We could take this rook first
though with check and then take the
queen so Nh7 was played to try and
parry Nf6 but now "pin on win"
rook takes h5 using the pin there
and the game actually ended here yeah
crushing absolutely crushing tactically
so let's see this game end position. If
Queen takes d4 Queen g4 is a massively
powerful move in this position. Massively
powerful and you might think ... hold on
okay it sets up a tactic against the
Queen. Why is this so powerful on
Queen takes c4 guess what the idea is?
Okay it's not to play Knight f6 check
here because black scoops up a lot of
pieces and actually better but no just a
quiet killer move rook takes h7 leaving
Nf6 on the table now for Queen takes
c4 and blacks totally busted in this
position for example Bishop d7 Knight f6
check and we take the rook and then
take the Queen. So what does black
actually do? Queen takes a2 check and
we play Queen b4 check here - look
the knight and Queen cooperating well for
a checkmate. Queen d5 we have Nf6
check winning the Queen. Queen b4 check
that's right yeah we've seen.We play Qb4 check which is even
better first. But Nxd5 
is fine. Here Qf1+
this doesn't help black - this position
because of check and now Queen g5
this is absolutely crushing. Let's see so
for example check and then Rd3
blacks in a sort of mating net as well
as losing material for example like this
This would be checkmating so all of these
beautiful relations also exist in the
final position. Let's just go back here
so rook takes h5 that was on Queen takes
d4
so on gxh5 we just take on g8 then
Knight f6 so here Qe8 checkmate Nf6 absolutely devastating. So on Knight
takes exf6+
then there's Qf8 check
here "Thorn" pawn
it's helping if here that's that and on
King c6 here then there's Queen c5
checkmate
so yeah just to take it to the game end
position
But to quote "Good Will Hunting"  - "it's
not your fault it's not your fault"
it's not alpha zeros fault. It is TCEC. 
Some of these start positions  in TCEC.
I think the stronger the the classical Alpha-Beta (AB) engines especially like Stockfish
is going to end up in basically a loss
for the weaker engines. Or even if
they're just as strong if it's cramping
like this with spectator pieces as a
feature of accepting a gambit maybe
there's just simply no defense. But Ng5
is like a major opening novelty really. I
believe now it should be the way forward
Knight g5 rather than Nf4 in
this gambit line. So a really truly
fascinating game and the AlphaZero team
did say chess is a bit more tactical
than Go so the neural network approach
is perhaps more effective in the realms
of the game Go because of the extreme
complexity that even building an
evaluation function is just a mammoth
task so but in chess yeah it seems we're
not quite at the end of the era for the
classical alpha beta engines and one
spin on that is just the extra
complexity. You could say the extra you
in a way you could say the extra
complexity in tactics make it go
beyond current engines and you have to
use a network approach. That sounds
a bit fuzzy and as if yeah there's
more scope to hang yourself in Go. And you
need the neural networks but yeah this
is a
an iconic game example of the
importance of chess tactics even in
closed positions especially in closed
positions maybe when there are spectator
pieces and tactics can smash through for
the side with greater piece of mobility. I
hope you enjoyed this one. A game for the
Stockfish fans!  Okay comments questions
appreciated. If you enjoyed this game
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