Grand Seiko Kodo Constant-force Tourbillon SLGT005

Quick specs Grand Seiko Kodo Constant-force Tourbillon SLGT005
Price: $ 365,000 | € 385.000 | approx. £ 280,000 | CHF 385’000
Size: 43.8 mm
Reference: SLGT005 – limited to 20 pieces

The Grand Seiko Kodo Constant-force Tourbillon SLGT005 is an almost 400k showcase of the tech level of the Japanese brand. A tourbillon with a constant energy supply for more precision, which was launched in 2022 as the reference SLGT003, following the SLGT001. Which followed the T0 Constant-force Tourbillon prototype. The 003 was limited to 20 pieces, the 001 is a unique piece. This new 005 Kodo (Japanese for “heartbeat”) version is limited to 20 pieces as well.

The new design is inspired by the daybreak, like almost all designs of Grand Seiko’s are inspired by the surroundings of their factories and ateliers. We don’t see the link, and it’s not necessary to come up with one as the watch speaks for itself. Compared to the 2022 ref. SLGT001 and ref. SLGT003 models the new one is exactly the same, apart from the color of the movement and pale blue sapphires. These are blue and purple (001) and purple (003) on the predecessors. The latter expressed “evening twilight”, the new one “light and shadow to evoke daybreak”.

Constant-force and tourbillon in one cage

Despite the inevitable little marketing blah it is still a wonderful looking timepiece. If you ever want to admire how a (hand-wound) mechanical watch works, this model reveals it all. Inside the 43.8-millimeter case, with Grand Seiko’s extra hard titanium on the outer case and platinum on the inner case, is a single axis with a constant-force mechanism and a tourbillon in one.

Which means there is nothing between the two mechanisms, so no loss of torque, no friction, no instability. Just one stable power transfer to the balance wheel for 50 hours. The tourbillon carriage inside rotates with a balance steadily vibrating at eight beats per second. The constant-force carriage on the outside rotates in one-second intervals. So, they placed a single red ruby on one of the arms as small seconds.

The Grand Seiko Kodo Constant-force Tourbillon SLGT005 has a power reserve of 72 hours

The movement of the Grand Seiko Kodo Constant-force Tourbillon SLGT005 is the hand-wound Grand Seiko caliber 9ST1. About 340 parts (why not provide the exact number?) make sure the whole mechanism functions, where the time indication has a power reserve of 72 hours. This reserve is indicated at the 8 o’clock position. And as this movement is developed by Grand Seiko designers and watchmakers at their Atelier in Ginza, the Atelier Ginza logo is engraved on the movement.

The model comes on a tanned white leather strap, hand-coated with urushi lacquer. It is closed with a platinum three-fold clasp with push button release. And you will also get an additional charcoal grey crocodile leather strap. Curious what other watches you can by with a price between 250,000 and 500,000? Click on our link.