This week's topic is: Japan going cashless
(be) king: to be on top and in control
make inroads: encroach on, advance at another's expense; sizable (increase): fairly large
mPOS: point of sale via mobile device
a smartphone or tablet that acts like a register
a lot of room for growth: many areas or ways in which something can get bigger and better
take steps to: do what is necessary to prepare for or begin doing something
roll out: officially launch or introduce a new product or service
offset: counteract (something) by having an equal and opposite force or effect
driving growth: something that consistently allows something to get bigger, popular and successful
betting big on: to invest or risk a lot of money in the belief that something will happen
push: something that moving something forward, in terms of business, to progress, improve and/or expand; bolster: support or strengthen.