New Delhi, Aug 12 - Grandmaster Praveen Thipsay made his fiftieth birthday a memorable occasion Wednesday as he defeated Surbir Lama of Nepal in the sixth round of the Asian Zone 3.2 Chess Championship. He now leads the table jointly with Neelotpal Das with five points.

Playing black side of four knights game, Thipsay overcame his Nepali rival in 58 moves while Neelotpal Das defeated Ahmed Ashraf without much struggle in just 27 moves.

In other sixth round encounters, overnight joint leader and local hope International Master Sriram Jha and second seed Grandmaster Deepan Chakkravarthy split the point after 20 moves while top seed Ziaur Rahman of Bangladesh defeated Amir Karim of Pakistan.

Another Indian International Master in the fray, K. Rathnakaran had it easy against Kesav Malla of Bhutan in the sixth round. After a fine run in the championship, Tunveer Gillani of Pakistan succumbed to his second straight defeat as he lost his sixth round match against Hapuarachchi HLM of Sri Lanka. Earlier in the fifth round, Gillani was beaten by Ziaur Rahman.

In the women's section, top seed International Master Tania Sachdev took the sole lead with 3.5 points after settling for half a point against Women Grand Master Nisha Mohota in the fifth round. Tania had anxious moments in the fifth round but managed to secure half a point after 40 moves as Nisha made some crucial mistakes towards the end.