I cringed quite a bit at GBP-JPY and EUR-JPY (my memory of JPY rate as it felt 'right' was £1=Y260, so the current exchange rate seems unbelievably bad), so I went and got myself a short contract that pays in JPY so that I don't feel so "exchange rate conscious" while I'm in Japan.
Last time I was there late last year, I ended up doing a big item shopping (bought myself a 9mm akoya pearl necklace), so I wanted to 'hedge my bet' by having some 'native' JPY in my pocket.