In a gorgeous wooden building dating to 1875, Innsyoutei (pronounced 'inshotei' and meaning 'rhyme of the pine cottage') has long been a favourite spot for fancy kaiseki-style meals while visiting Ueno-kōen. Without a booking (essential for dinner) you'll have a long wait, but it's worth it. Lunchtime bentō (boxed meals) offer beautifully presented morsels and are great value.
Between lunch and dinner the attached teahouse serves matcha (powdered green tea) and traditional desserts from ¥600.