Go record format

Go games are usually noted down in SGF format (either FF[3] or FF[4]). The files usually have an .sgf extension. However, one also meets a nonstandard form of SGF. Let me call it (just on this page) SGF2.

Look at the Nihon Ki-in records of the World Amateur Go Championships.

21st (1999), 22nd (2000): Files in UGZ (compressed UGF) format, with .ugz extensions.
23rd (2001), 24th (2002), 25th (2004): Files in UGF format, with .ugi extensions.
26th (2005), 27th (2006), 28th (2007): Files in SGF format, with .sgf extensions.
29th (2008), 30th (2009), 31st (2010), 32nd (2011), 33rd (2012), 34th (2013): Files in SGF2 format, with .sgf extensions.

SGF2

A typical SGF file starts

(;
SZ[19]
GN[The 28th WAGC Round6]
DT[2007/05/30]
PC[Tokyo NihonKiin]
PB[KUIN(NED]
PW[BAZYNSKI(POL]
KM[6.5]
RE[B won by resign.]
;B[pc]
...

A typical SGF2 file starts

(
TE[The 29th WAGC Round 1]
RD[2008.5.28]
PC[Nihonkiin, Tokyo]
TM[1 hour 30 minutes]
LT[10/15 Canadian byo-yomi]
KO[6.5 pts]
RE[White won by resign.]
PB[Leon MATOH]
BR[27-SVN]
PW[Frank JANSSEN]
WR[7-NED]
GK[1]
;B[pd]
...

Differences are:

(i) The start is ( instead of (;. This means that some SGF readers won't find any game in an SGF2 record.

(ii) Some properties have different names. Mainly:

SGF SGF2 meaning

GM[1] GK[1] game (go)

DT[..] RD[..] date

EV[..] TE[..] event

KM[..] KO[..] komi

OT[..] LT[..] overtime, byo-yomi

HA[..] HD[..] handicap (with built-in AB)

SGF	SGF2	meaning
GM[1]	GK[1]	game (go)
DT[..]	RD[..]	date
EV[..]	TE[..]	event
KM[..]	KO[..]	komi
OT[..]	LT[..]	overtime, byo-yomi
HA[..]	HD[..]	handicap (with built-in AB)

In SGF the property TE is found as TE[1], tesuji; KO is found as KO[], illegal move (gnugo uses IL[]); LT is found in SGF FF[3] as LT[], loss on time is enforced.

HD[3] sometimes implies AB[dd][dp][pd] and sometimes AB[dp][pd][pp].

(iii) SGF files usually are in ASCII or UTF-8 (sometimes with a CA property indicating the character set). SGF2 files usually are in ASCII or CP932 (SJIS).

Games in SGF2 format are also found e.g. on baduk.lg.co.kr and www.cyberoro.com. Occasionally one sees traces elsewhere, like RD instead of DT in an otherwise regular SGF file, or both GK[1] and GM[1] in the same file.

I don't know who invented this format, or why it is useful.