Is TWSE open on Monday 11 February 2013?

No. TWSE is closed on Monday 11 February 2013 for Chinese New Year. It reopens on Monday 18 February 2013.

Chinese New Year

Related markets on 11 Feb 2013

TSE Tokyo	National Foundation Day
HKEX	The second day of Chinese New Year
SSE	Chinese New Year (Spring Festival)
KRX	Seollal (New Year's Day by the lunar)
NSE	09:15–15:30
SGX	Chinese New Year
ASX	10:00–16:00
NYSE	09:30–16:00
Nasdaq	09:30–16:00
TSX	09:30–16:00