US GM Timur Gareyev has been playing it in open tournaments.  Nepo and Rapport have also messed around with it, mainly in blitz.  Notwithstanding Magnus's apparent "endorsement" (in quotes because, given his comments, I'm not sure he thinks its any good.  Maybe he feels obligated to play it since its also known as the Norwegian Rat), I would not play it in a real game.  

It is, however, fun to play in blitz and bullet.  I've just been goofing around -- no real proper study -- but seems to me that 3.Nc3 d5 (3..d6 would be a Pirc) 4.e5 Ne4 is better for White.  In the main lines after 3.e5 Nh5, I've generally done OK when White's played 4.Be2 5.Bxh5.  Don't know that its any good, but its messy and there's chances.  Things get more difficult when White plays to restrict the Nh5 (g7) rather than take it.  I have so far found 4.Nf3/5.h3 to be the most annoying.   

I don't have the book, and searching online I wasn't able to find a copy anywhere. The information was from the chessville.com review. I'm not sure Bickford's book is worth hunting down, instead you could just use a database, some online resources, and your own analysis. Quote:
Quote:


Bickford's table of contents, cribbed from schachversand.de
01 Introduction
History
Outline
References
07 Part 1: Early Alternatives
Variation 1-A: 4 c4
Variation 1-B: 4 f4
Variation 1-C: 4 g4
21 Part 2: 4 Bc4 d5
Variation 2-A: 5 Bd3
Variation 2-B: 5 Be2
27 Part 3: 4 Nf3
Variation 3-A: 4...d5
Variation 3-B: 4...d6
39 Part 4: 4 Nc3 d5
Variation 4-A: Bd3
Variation 4-B: Be3
Variation 4-C: Nf3
Variation 4-A: 5 f4
Variation 4-B: 5 g4
51 Part 5: Nc3 d5 5 Be2
Variation 5-A: 5...Nc6
Variation 5-B: 5...Ng7
61 Part 6: 4 Be2 Ng7
Variation 6-A: 5 Bh6
Variation 6-B: 5 Nf3
69 Part 7: 4 Be2 d6
Variation 7-A: 5 f4
Variation 7-B: 5 Nf3
Main Line
4 Be2 d6 5 Bh5 gh5 6 Qh5 de5
77 Part 8: 7 de5 Qd5 8 Nf3 Qe4 9 Be3 Qc2
Variation 8-A: 10 Nc3
Variation 8-B: 10 0-0
85 Part 9: 7 Qe5 Rg8
Variation 9-A: 8 c3
Variation 9-B: 8 Bf4
Variation 9-C: 8 Ne2
Variation 9-D: 8 Qe4
https://www.schachversand.de/en/the-north-sea-variation-of-the-modern-defence.ht...

I attached the 13 games (1988-2010) from brooklyn64.com. A quick check of ChessBase online for the first five games found them all, I suppose the other eight are in there as well.

kylemeister wrote on 04/02/19 at 21:10:39:


Interestingly, that game transposed into a ..Qd6 Scandinavian where Black was fine.  6..Bg7 had been played before.

The following link was posted on the English Chess Forum at the time of Adams - Carlsen. 
http://chessville.com/reviews/NorthSeaVariationModernDefence.htm

Jim Bickford (2007 Syzygy Publishing Inc.) The North Sea Variation of the Modern Defense (ECO B06) 
Reviewed by Rick Kennedy 
https://web.archive.org/web/20100927182127/http://chessville.com/reviews/NorthSe...

Although light on analysis the review has good background and some bibliographic value. It also quotes the key, according to Harding, game Stern - Hjorth, corr 1994. The Harding article is also not available online, but his analysis might be available on one of his correspondence disks.

A little off topic ... 
https://woodsmokeblog.wordpress.com/2019/01/26/on-rolf-martens-1942-2008/

The North Sea could just be Carlsen fooling around, was he playing for money? And for those of us who, due to work restrictions, cannot access youtube, could you post some of the moves? Sielecki said white just needed to avoid 4.Be2, he gave 4.Nf3 and simple (of course!) chess as leading to some plus.

Here is a working link to Stefan Buecker's article mentioned in #14. His "Main Line" follows 4.Be2, but in the note at move four he says 4.Nf3 "can even be considered as the main line". 

The North Sea Defense (May 2008) 
https://web.archive.org/web/20101205134856/http://www.chesscafe.com/text/kaiss33...

Magnus Carlsen's blog is still available, but the other three links given in this thread are all broken. Tells us a lesson about the modern media. It is a pity, in particular, that Rolf Martens' online debate of his ideas are gone (and yes, I've checked "waybackmachine"). 

In the following game, 7...Qd5 was already recommended by Martens and correctly assessed as equal. 10....Qg6 = was more precise. After Black misses 20...Nc5 (=), he gets into trouble. 

A bit off-topic, but in Round 10 Carlsen played 5...Bb4 in the Main Line Advance Caro-Kann.

Viking wrote on 09/30/10 at 16:51:39:


Exactly. Magnus came out of the opening with a very reasonable position. But because he lost I see comments on the internet like trash, junk, dodgy, rude to his teammates etc. Mildly annoying. 

Clearly As I remember he came terribly close to losing to Adams in the London tournament last winter, so you'd think he'd take him half way seriously!

I guess its hard for him to get motivated when he's not really playing for anything beyond pride.

It seems Magnus just wants to play funchess, his play against Adams was just begging for problems and a loss. It seems, he doesn´t take his opponents seriously, maybe Garri should take a call with him.

Yes, North Sea not for casual swimmers.

I would be interested in Carlsens thought process in deciding to play this vs Adams.
Though I do think the opening in this game went ok for Black.

... and now Carlsen plays it versus a 2700+!!
Maybe this opening has no refutation after all.
It certainly is a different way to go.

Tim Harding wrote about the defense on SOAK http://www.soak.com/topic/chess/article/tshow/15906/the+north+sea+defence+refute...

"THE NORTH SEA DEFENCE REFUTED?
Some years ago, Swedish analysts came up with a hybrid of the Modern and Alekhine's Defences that goes 1 e4 g6 2 d4 Nf6 3 e5 Nh5 4 Nf3 d6. Known as the North Sea Defence, it is still an almost unknown variation -- not mentioned in most theory books.

The defence took a big knock in the high-level postal game D.Stern-G.Hjorth, 1994, when White played 5 Bc4 Nc6 6 Ng5! e6 7 g4! Be7 (If7...Ng7 8 Qf3 Qe7 9 Bb5 Bd7 10 Ne4 when 10...Nxd4 or Nxe5 fails to 11 Nf6+ Kd8 12 Qxb7.) and now Stern played simply 8 Nf3! when the black knight gets stuck on the bad square g7.

GM Julian Hodgson and some others have tried to revive this defence by 5...d5. However, this means Black abandons any hope of quick pressure against the white centre. 

- Tim Harding "

Thanks for this. Personally I'd far rather brave the 4 ...d6 lines than shuffle around with 4 ...Ng7, even though that might be playable by analogy with the Alekhine's.

In MNb's line with 7 ...de 8 fe, might 8 ...Nc6 be an improvement?

According to latest NIC, russian team championship'05 saw Morozevich doing a knight fianchetto 1. e4 g6 2. d4 Nf6 3. e5 Nh5 4. Be2 Ng7!? (Burmakin-Morozevich). He managed to draw. 

Seems too provocative, even for most Alekhine players!

Quote:


Quite right!

Generally speaking you're not missing too much from not knowing swedish, as the forum visitors often get out of line or order...  

Basically one guy, Mikael Johansson (no relative of mine btw), with about +2300 says he has a refutation but won't show it - sounds familiar from the dragon forum here,, doesn't it? - but he offered to play a side bet match against Martens 'proving' his refutation, which was not accepted, as Martens is only interested in the teoretical side. This nonmatch lead to a lot of speculation and so forth...

At the moment they're mostly debating the Sicilian Left Hook variation in another thread, which is of course another Marten's invention: 

1.e4 c5 2.Sf3 Sc6 3.d4 cxd4 4.Sxd4 Sh6!?N - if I remember correctly, Rolf M. won the Swedish blitz championship largely thanks to this variation in 1986 or there abouts. As far as I know it has never been played in a longer tournament game, like so many of RM's many other ideas...

So far MJ claims 5.Bxh6 gxh6 6.c3 +/- while the rest of us seem to believe in = / =+ It will be interesting to see who wins, if any...   

Sounds interesting!
I think I will even let my beloved dragon take a rest (!) and try this on the internet . I will tell you what my experiences were.
The thread in the Swedish forum seems to be very interesting, unfortunately I don't speak this language.
Did I guess right that "dragomkastning" means "Zugumstellung"/"move order transposition"? 

A similar idea is known in the Semi-Accelerated Dragon: 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 5.Nxc6 bxc6 6.e5 Nh5!?
I have come to the conclusion, that simple development here with 7.Be2 gives White a solid edge, not with the intention to exchange on h5 as soon as possible.
Comparing with the North Sea Defence though (I love that name, the Netherlands have beautiful North Sea beaches, which alas are to crowdy on hot days), it seems as if the White knight on g1 in stead of d4 benefits Black.
What about 1.e4 g6 2.d4 Nf6 3.e5 Nh5 4.Be2 d6 5.f4 dxe5 6.fxe5 Nc6 7.f3 Bf5 8.Be3 ?