(CNN) -- Yani Tseng carded a second straight 68 to hold a four-shot halfway lead in the British Women's Open at Royal Birkdale.
The 21-year-old from Taiwan carded five birdies and only one bogey for an eight-under 136 total on the seaside links.
Amy Yang (71) and Americans Cristie Kerr (67) and Brittany Lincicome (71) were her closest challengers, but Scotland's defending champion, Catriona Matthew, carded a sorry 81 to miss the cut.
Two-time major winner Kerr shot the best round of the day in drizzly conditions with six birdies to take closer order.
But Tseng responded with three birdies coming home to keep a big lead with two rounds to go.
Australian Katherine Hull, who had shared the first round lead with Tseng, slipped back with a two-over 74 and is bracketed with LPGA money list leader Jiyai Shin, of Korea, who shot another 71 for two-under 142.
American Michelle Wie and England's veteran star Laura Davies are both on two over and set to comfortably make the cut which is likely at four over.
Wie followed her opening 70 with a 76 to slip out of contention while four-time major winner Davies had a 74 as they trailed Tseng and the other leaders.