I actually taught him Maths, not chess, but many thanks for the thought!

I still call this the P-K4 Defence. It can often lead to a Reverse Sicilian, but with the Black pieces I preferred a type of Dutch Defence System, following with 2...d6 and 3...f5. Oddly enough, with the White pieces, I had many games that transposed into Maroczy Bind Sicilians.

a kind of position that I don't mind playing either side.

A nice weapon to have for either side

As Black I used to prefer the lines involving an early ...f5 as active and aggressive. My experience with them on Gameknot has been less fortunate, as White is often able to suck the life out of the position. Still, now that White has developed a knight to f3, that might not be so easy for him. My usual sequence with the White pieces was almost invariably 1.c4... 2.Nc3... 3.g3... 4.Bg2. It was never clear whether the knight's preferred square was f3, e2 or even h3. Here's a fairly exciting example from my early Gameknot days: game

You mean 4...e4, right?

White must be really pleased to have got a 'Levenfish' with a move in hand...

I used to play Levenfish players quite a bit. Been quite awhile since I encountered one I believe

Fritz calls this +o.o8 for white, so Levenfish or not, a pretty equal position. So as it is most of the time, we will see who goes off the track first.

I would probably have played 5...d6, myself...

4th best in the DB or not Fritz says best.

I believe I would've played this. There is nothing white can challenge d4 or the bishop with immediately, so it's relatively safe.

The upside of double fianchettos is that they bring the centre under a crossfire. The downside is that the bishops aren't really working together.

No a5 doesn't prevent Na4, but it means that Na4 doesn't win the two bishops as the Bc5 can retreat to a7.

I can see why you might decide that the c5-bishop is an asset you would prefer to keep. But there is something to be said for allowing White to waste time and his better knight to wipe it out. Knights might well prove the handier pieces in the semi-closed sort of game you have here.

I agree with archduke, it is unclear at this poinr whether the B is better than the N.

In this position, I slightly favor the knights, but who knows? Something may open up later and the bishops may be needed.

Good heavens Viktor Pupols must be cracking on a bit. I see a reference to him in respect of a Latvian Gambit in my MCO11 (1972). I looked him up. He's still around, aged 82.

Love a good ole reference to my favorite toy opening on black as a club player -- The Latvian Gambit I mean  

I didn't know about that game when I was playing this!

I am puzzled why Black retired the bishop when it was not under threat. It is certainly not to make rook for anything. Possibly Black had reason to expect White to play d3-d4 soon, and wanted to keep the option of playing ...e4. Well, White does play 9.d4... and sure enough...

To answer the previous comment by archduke_piccolo, yes I wanted to meet d3-d4 with e5-e4 and to do that safely I need to retreat the bishop.

Black is pretty well set up for K-side operations.