Baltalimanı Japanese Garden is a small landscaped garden on the European side of the Bosphorus, built with support from Shimonoseki, one of Istanbul's sister cities. It has a tea room, ponds, waterfalls, and a cherry-tree lane.
It is a calm add-on to the northern Bosphorus sights rather than a headline stop, useful when you want a quiet break between waterfront walks and fortress visits.