Watanabe Kobo Handmade Watch Open Heart Manual Winding Brass Cushion Case 38mm Arabic Numerals Sewing Machine Stitch Belt [BHW144-MS]

Masaaki Watanabe of Watanabe Studio is a watch maker who creates watches one by one by hand in his studio located in downtown Tokyo. He creates many watches that are full of the deep expression and warmth that can only be achieved through handcrafting.

Watanabe handcrafts everything from making the watch parts such as the case, dial, and strap to assembling them.

This open heart model allows you to see the movement of the watch's mechanism through part of the dial. It moves like a human heartbeat, making it a soothing piece.

The small window through which you can see the "Heart (machine)" is an accent (the belt color in the photo is "camel x beige")

This watch, named "Open Heart," is a hand-wound mechanical wristwatch with a small window on the dial.

The movement can be seen through a small window, and it looks just like a human heartbeat. The quiet ticking of the second hand is also soothing.

The manual winding type winds up the mainspring by manually turning the crown. The back of the case is skeletonized, allowing you to enjoy the movement of the ticking movement.


The case size is 38mm, a standard size that is easy for both men and women to wear.

The antique brass case has the charm that can only be achieved through handcrafting.
The more you use it, the more antique the feel will become.

By fully winding the mainspring using the crown on the right, the watch will continue to run for one to one and a half days.

It has a see-through case back, so you can enjoy watching the movement.

Now that hassle-free automatic and quartz watches have become widespread, an increasing number of watch enthusiasts are choosing manual winding watches, which require the manual effort of winding the mainspring by hand.

The effort of winding a mainspring by hand feels like something that enriches the soul by interacting with the object, like grinding coffee beans in a mill.

The belt is made of genuine cowhide leather with a nice texture. It is thick and sturdy, highly durable, and has an elegant appearance.

The belt is made of genuine tanned cowhide.

The machine stitched lines add a subtle accent.

Buckle part

Overall (Click to enlarge)

The moderate weight of the case and the elegance of the cowhide strap add a touch of class to any adult look. It is also recommended for vintage outfits and work styles.

It goes perfectly with chic styles, elegant styles, and antique dresses.
(Women, arm circumference approx. 15cm)

It has a moderate presence and can be used in business situations. (Men's wrist circumference: approx. 17 cm)

It is also recommended as a gift with heart.


The perfect size for both men and women. The design is mature and elegant.

The warm atmosphere of brass goes well with casual styles.

It is recommended not only for yourself, but also as a gift or present for birthdays, anniversaries, Christmas, Valentine's Day, White Day, Father's Day, Mother's Day, Respect for the Aged Day, and for graduation and employment celebrations.

You can choose the belt color and stitch color.

Machine stitched belts are
You can choose from five colors: camel x beige, dark brown x brown, dark brown x black, black x brown, and black x black.

Choose your favorite belt color to make a special one just for you...

We also offer a smaller 34mm case model.

Click on the image to move to the page.

Material, processing, and size

Materials and Processing	[Movement] Manual winding, 3 hands [Case] ​​Brass / Stainless steel back, glass (skeleton back) [Belt] Genuine leather (tanned cowhide) / machine stitching [Windshield] Glass
size	[Case] ​​Dial diameter: 34mm / Case: Maximum width 38mm / Thickness: Approximately 12mm [Belt] Width: 21mm / Thickness: Approx. 4mm / Suitable arm size: 13cm to 17.5cm [Weight] Approx. 70g

Important points to note when ordering

This is a made-to-order product, so it will take about 3 weeks to 1 month to deliver. During gift seasons such as Christmas, Valentine's Day, and White Day, production tends to take longer. If you are thinking of buying it as a gift, please take the delivery date into consideration when ordering.

The warranty period is one year from the date of purchase. However, this only applies to internal failures, and does not cover exterior parts such as the case or belt.

This product is not waterproof, so please be careful when using it on rainy days or when working around water.

This is a hand-wound watch, so if you do not wind the mainspring, it will stop. Please be careful not to wind the mainspring too much as this may cause it to break.

Manual winding watches do not have a second hand stop function. The second hand will not stop even when you adjust the time.

The color of the eyelets, buckle, etc. may change depending on the color of the case and belt. We hope you will understand this as one of the characteristics and charms of handmade watches and place your order.