What is Kameiwa Cave?
Kameiwa Cave's Heart-Shaped Light Reflection! When can you see it?
Things to See in Shimizu Keiryu Park: Not Just Kameiwa Cave!
Access: How to get to Kameiwa Cave

Only a day-trip's distance away from Tokyo, on the Boso Peninsula of Chiba Prefecture, is Kameiwa Cave. Only in the past few years, the beauty of this cave has captivated the hearts of many travelers. The cave is not only covered in lush nature reminiscent of a Studio Ghibli movie; it also has a certain "heart-shaped" scenery that shows itself under the right conditions. This scenery was what went viral on social media, and made Kameiwa Cave an immediate hit with tourists in Japan.
With images, this article will introduce the picturesque Kameiwa Cave, its best views, and things to do in the area!

About Kameiwa Cave

Entrance to Shimizu Keiryu Hiroba

Kameiwa Cave is located in Shimizu Keiryu Park, in the city of Kimitsu, Chiba Prefecture. The public park is equipped with a nice walking trail that can be taken to explore the park.
Kameiwa Cave is actually a man-made cave. Around 1660, the cave was made to serve as a tunnel to help with irrigating nearby rice fields.
This irrigation technique is called “kawa-mawashi”, and some locals call the cave “kawa-mawashi tunnel”. The name Kameiwa Cave was given due to one of the rocks in the cave resembling a turtle (kame, 亀).

The Heart-Shaped Light Reflection! Kameiwa Cave's Famed Sight

Kameiwa Cave and a stream

Kameiwa Cave is surrounded by lush, green leaves, and the sight is ethereal and dream-like.
The scenery changes by season – in the summer, the area is a lively green, while in the autumn season you can enjoy the spectacular red of fall foliage.

The perfect heart-shaped reflection!

The most well-known site at Kameiwa Cave is this heart-shaped reflection it creates.
Under the right lighting and timing, sunlight shines through into the cave and creates a reflection in the water. The heart-shaped reflection can only be seen when all of the following conditions are met.

When you can see the Heart at Kameiwa Cave?

Sunlight shining through the cave

To see a perfect heart-shaped reflection, you should visit in the early morning hours in around March or September, or a few days before the equinoxes.
It must be sunny and clear, and there must be some humidity in the air as well.
It is also important that there is little to no wind. The area of the cave is not particularly known for strong winds, so this condition might be less of a worry.

Kameiwa Cave is beautiful even without the heart-shaped lights

Even if you couldn’t catch the heart reflection, you should still be greeted with a beautiful view of the sunlight shining through the cave.
When taking photos of the sunlight shining through the cave, angles are very important.
You might even want to step into the river to get the right angles, so wearing rain boots or sandals is recommended.


The area of the cave is closed off for entry. Visitors are not allowed to get near the cave. When taking photos or going near the cave, make sure to never cross the line that is placed.

Things to See in Shimizu Keiryu Park: Not Just Kameiwa Cave!

The path inside the park

Aside from Kameiwa Cave, there are plenty of sights at Keiryu Hiroba Park.

Nomizo Falls

Nomizo Falls

Although Nomizo Falls is called “Nomizo Falls”, it technically is not a waterfall. There once was an agricultural water mill here, and the groove formed by it looked like a waterfall.

You can see Nomizo Falls from the pathway. If you look closely, you can find a heart-shaped groove.

The Bell of Happiness

Bell of Happiness

The Bell of Happiness was donated to the park in 2011. It is designed in the shape of a turtle, which is said to bring luck in fulfilling wishes and prayers.

When the bell is rung, it is said that luck and happiness is brought out from the Kameiwa rock, the turtle shaped rock in the cave.

Firefly Watching

At Keiryu Hiroba Park, you can see fireflies between June and August. Whether they can be seen or not depends greatly on luck. If you are able to see them, you will be welcomed to an unforgettable, dreamlike spectacle.

Access: How to get to Kameiwa Cave

Nearest station: Kimitsu Furusato Bussankan 君津ふるさと物産館 (Bus Stop)

From Tokyo Station to Kameiwa Cave

【Tokyo Sta.】Highway Bus Aqusea / for Awakamogawa
→【Kimitsu Furusato Bussankan Bus Stop】
→ about a 20-minute walk

From Chiba Station to Kameiwa Cave

【Chiba Sta.】Highway Bus Kapina / for Awakamogawa
→【Kimitsu Furusato Bussankan Bus Stop】
→ about a 20-minute walk

From Narita Airport to Kameiwa Cave

【Narita Airport Sta.】JR Narita Line / for Tokyo
→【Chiba Sta.】Highway Bus Kapina / for Awakamogawa
→【Kimitsu Furusato Bussankan Bus Stop】
→ about a 20-minute walk

A Mystical Sight, only at Kameiwa Cave

When Kamiewa Cave first began to gain widespread popularity, the location of the heart-shaped reflection was mistakenly circulated as Nomizo Falls. Nomizo Falls is a beautiful sight in itself, but a separate one from Kameiwa Cave. Make sure you have the right place in mind when visiting!


Sasa, Kimitsu-shi, Chiba
Open all day
Open year-round

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