Tokyo's taste for high-end meat is maturing fast. For the cognoscenti, breed, provenance and fat content have long been critical. Now add one more key factor: aging. That's the focus at several new venues.

At Ruby Jack's, the slick, chic steakhouse that opened in Ark Hills in Akasaka in April, premium beef is the name of the game — just as you'd guess from the illuminated showcase with its haunches and slabs, which forms the centerpiece of the gleaming, glass-encased dining room.

Both sirloin and ribeye steaks are A3 wagyū — local beef of certified origin; medium marbling of the fat — that is dry-aged 45 days. Succulent and tender, rich but not too fatty, this is premium beef at prices to match (¥11,000 per 300 grams of sirloin). For those who prefer their beef imported, there is USDA prime (ribeye or New York cut) or Australian Black Angus (fillet or T-bone) at rather less eye-watering sticker prices.