something is clearly wrong in the list of chess players

[Uri Blass]

https://chess-db.com/public/execute.jsp ... =a&start=0

I look for the list of chess players in israel and I see some players twice

For example

I have the following lines

1 2805677 Gelfand, Boris GM 2686 1968 154
2521 9010059402 Gelfand, Boris 0 2733 1968 i SK Schwaebisch Hall 2

I do not know the source of the second line

games are the same games

https://chess-db.com/public/pinfo.jsp?id=2805677
https://chess-db.com/public/pinfo.jsp?id=9010059402

same happen also with other top players not from israel that for some reason I can see twice.

for example:

https://chess-db.com/public/pinfo.jsp?id=9010665915
https://chess-db.com/public/pinfo.jsp?id=4168119

[Dann Corbit]

Sometimes dups happen when players change from one country to another.

[Guenther]

https://chess-db.com/public/execute.jsp ... =a&start=0

I look for the list of chess players in israel and I see some players twice

For example

I have the following lines

1 2805677 Gelfand, Boris GM 2686 1968 154
2521 9010059402 Gelfand, Boris 0 2733 1968 i SK Schwaebisch Hall 2

I do not know the source of the second line

games are the same games

https://chess-db.com/public/pinfo.jsp?id=2805677
https://chess-db.com/public/pinfo.jsp?id=9010059402

same happen also with other top players not from israel that for some reason I can see twice.

for example:

https://chess-db.com/public/pinfo.jsp?id=9010665915
https://chess-db.com/public/pinfo.jsp?id=4168119

Both entries for the players you listed are different, because they count for different rating organisations,
one for FIDE Elo and one for national rating (wrongly called 'National Elo'), whatever nation that might be,
surely some players even have national ratings, in several countries.