The 1828 1/2c. I'm quite partial to high grade holed or slightly damaged pieces - nice to look at and fits the budget! Not to mention there's usually a story to tell.
The cash coin is listed in the '95 edition as C4.2, ND (1769-1860) Japan 4 mon. .30 VG, .50 F, 1 VF, 3 EF
Japanese cash coins are considerably less common than Chinese coins. Annamese (Vietnamese) are a bit scarcer, while Korean ones are rarely seen (though there are many that catalogue at $2 or less)