Kratzer and Shimoyama (2002) suggest that the German free choice (FC) indefinite irgendein triggers FC effects due to its domain widening action. In this paper, the author shows that Korean indefinite amwu-, unlike wh-indefinites, induces domain widening, which is responsible for several semantic effects including FC effects. Furthermore, it is observed that the scalar focus particle -lato (NPI-even) also gives rise to FC effects in Korean. The FC effect induced by -lato is different from the one caused by domain widening with respect to cancelability and orientation. That is, the -lato FC is not cancelable, and is always oriented towards the speaker. Finally, a compositional analysis of -lato-FCIs is proposed: -lato is characterized as NPI-even à la Guerzoni (2005), and its most likely presupposition together with existential presupposition yields the FC effects.