This beautiful illumination is called “Ao no Doukutsu”, meaning Blue Grotto, was in Nakameguro in 2014. It has relocated to Yoyogi park this year (2016).
The illumination runs from November 22nd through January 9th. I didn’t have a chance to go to the Nakameguro Illumination, but I’ve heard they moved the illumination in favor of the much wider street of Yoyogi park.
The Illumination starts on Shibuya Koen Dori (Shibuya park street) and those Japanese Zelkova trees were lit up for your 750 m walk. I recommend stopping by there when you are in the downtown Tokyo area. Check out the Illumination website to see the video for directions. – Mai Takahashi, December 2016
Ao no Doukutsu, Shibuya : http://shibuya-aonodokutsu.jp/
Illumination time in 2016: 5 pm – 11 pm, November 22nd – January 9th (the illumination starts at 7 pm on November 23rd, December 4th, December 25th, and January 9th)
To get to the illumination spot, the closest station is Shibuya. The street is on the opposite side of Meji Shrine in Yoyogi park, so make sure to get off at Shibuya Station, not Harajuku station.
To Shibuya station, take Ome/Chuo line to Shinjuku, and then transfer to Yamanote line towards Shibuya and Shinagawa.
From Shibuya station, exit from Hachiko exit and then cross the famous crowded intersection. And then take the street that is to the right of the building that is all glass and has a large tv display. You will see a Starbucks and TSUTAYA video store in this building. Keep walking until you see the blue lights on the trees.
Once you find the blue trees, follow them to Yoyogi park.