Topband: understanding 160 meter propagation

[PACER99 at aol.com]

for the propagation experts:
 
happened during this weekend 160 meter contest:
 
in general conditions were very poor with just a few Europeans worked on  
Friday and nothing on Saturday.
 
between 1130Z and 1420Z(sunrise) on the first morning the band opened with  
signals from south and north Asia being extremely strong. JA's over S9, 
BV/BA's  the same. worked 4 zone 18 stations  where i had only worked 2 during  
the past 30 years. 
 
something was cooking but i dont know what. any ideas?
 
larry
n7dd