Yoshi Restaurant at Forum Shopping Mall is not bad.
If you want to impress your business partners or dates, bring them to Keyaki.
Nami at Shangri La is a good Japanese restaurant all round.
Sister restaurant of Sushi Kimura, The Gyu Bar specializes in wagyu yakiniku, serving premium Wa-OH beef imported chilled (not frozen) from Kumamoto prefecture on Kyushu island. They have an omakase menu: 6-course lunch menu for $68++ or 10-course dinner for $138++.
Kindori at CHIJmes serves Japanese fried chicken and craft beers.
Niku Kin 肉金, a yakinuku at Craig Road, aims to make 100% authentic Hokkaido wagyu (A3 to A4 grade) affordable for the public.
Yakiniku-Oh Goen at Tanjong Pagar serves super umami yakiniku, using imported cow from Hokkaido. By cow, I really mean cow. They import entire cows.