came back from thailand ,i watched most of the s-1 or kings cup,the funny thing for every weight there is around 30 contestants it takes 10 days to finish the tournament. and i always thought 4 contestants in the same weight was hard.
I think what you saw was Amatuer World Titles, the may have called it something to do with the King. S1 is in one night and Kings Birthday fights are in December.
The S-1 do all sorts of co-promotions with other events. Kings Birthday, The Princes Cup, WMC World Title bouts, WBC bouts etc. I worked for them several years back in conjunction with the Kings Cup. The year that Longsongkram beat Wanlop Sithpolek. We also fielded two fighters that year... Jean Charles Skarbowski and Bruce 'The Preacher' McFee.