What happened with Japanese stars on IGS?

  I tried to find famous professional players on IGS, but most of them have
expired accounts or last access in 2003-2007. Cho U, Kobayashi Koichi, Cho Chikun,
Kobayashi Satoru, Yoda Norimoto, Takao Sinji, Yamashiro Hiroshi,Ryu Shikun,
Hikosaka Naoto ... They were very active few years ago, but it's hard to meet them nowadays.
  IGS was the first Go server in the world and in 90's it was not possible to
change the server. Nowadays there are lot of possibilities! Both Cyberoro and Tygem,
for example, have Japanese clients available.
Sol.ch wrote us about Kobayshi Koichi, who plays on Tygem now.
I checked Cyberoro rankings and found that there are 20 Japanese accounts in
best 50 list. These 20 players are top professionals, of course. I don't know
their real names, but here is the list with winning scores:

5 chouetu   7-dan, 323W-28L 34,600 92.02%

7 gentoku  7-dan 148W-54L 34,491 73.27%

8 tenzaru1   7-dan 70W- 19L 34,482 78.65%

10 regain   7-dan 2,023W- 583L 34,476 77.63%

14 youkoo   7-dan 333W- 76L 34,427 81.42%

15 kakuei   7-dan 118W-45L 34,423 72.39%

19 kagerou   7-dan 70W-22L 34,367 76.09%

24 firef   7-dan 282W-119L 34,362 70.32%

27 debiruman   7-dan 1,122W- 533L 34,326 67.79%

29 glay1   7-dan 40W- 8L 34,318 83.33%

30 tubo   7-dan 1,113W- 392L 34,317 73.95%

33 aki814   7-dan 636W- 300L 34,276 67.95%

34 pino306   7-dan 481W- 277L 34,273 63.46%

36 time   7-dan 1,405W- 731L 34,246 65.78%

42 nuppesso   7-dan 55W- 12L 34,218 82.09%

43 autumn   7-dan 128W- 71L 34,209 64.32%

45 xenlon   7-dan 86W- 30L 34,207 74.14%

46 hereborasu   7-dan  291W- 202L 34,191 59.03%

48 merumo   7-dan 221W- 103L 34,184 68.21%

50 stylish   7-dan 330W- 132L 34,176 71.43%

All of them started to play Go online from IGS ...