In & Around:
品川第三砲台跡 or "shinagawadaisanhodaiato", one of the original Edo-era battery islands, as viewed from the Rainbow Bridge south side.
See shooting location map below.
This place is very nice during sunset hour. The sun will set behind Tokyo skyline which is the opposite of this island. This island is on the south side of the bridge. If you walk a bit more down the bridge (toward Odaiba) you will see a small star lead to below the bridge. You can cross between north and south side of the bridge via that small star. To get Tokyo city view, you will have to be on the North side of the bridge.
I used a 15 mm on 1.5 crop sensor for this photo. Tripod is ok to use on the bridge. The bridge is shaken all the time (via wind, trains and cars), even on a tripod it can be hard to use telephoto lens + slow shutter speed while you are on the bridge.