My shop only sells genuine products, so please feel free to purchase. We also have a large inventory of excellent vintage and antique watches → #nekoneko Please read the profile before purchasing. ● Product Description [Rare, Beautiful, Good Accuracy] This is a self-winding chronograph "Challenge Timer" manufactured in the 1970s, incorporating Citizen's finest technology. This model is a sibling model that was in the lineup at the same time as the so-called "Tsunochrono," and it uses a "Blacky (black oxide film on aluminum alloy)" case, which was cutting-edge technology at the time. The design embodies the retro-future of the 70s, with the lightweight and sharp black texture and the orange chrono hands and lower subdials. The timegrapher measurement shows a daily rate of +14 seconds, maintaining amazing accuracy for a mechanical watch from over half a century ago, making it a highly practical piece. ● Detailed Information ・ Model Name: CITIZEN CHRONOGRAPH (Challenge Timer) ・ Case Material: BLS (Blacky / Stainless Steel Back) ・ Dial Color: Black ・ Made in Japan ・ Year of Manufacture: 1972 ・ Movement: Cal.8100 (23 jewels, self-winding, with flyback function) ● Case Width: Approximately 39mm (including the crown) Lug Width: Approximately 19mm Wrist Size: Approximately 17cm (Please allow for some margin of error) ● Features ・ Equipped with the 81 series movement: High-end specifications with a vertical clutch and flyback function ・ Day-date display ・ Equipped with the original Blacky bracelet ● Condition of the Product ・ Accuracy: Very good, approximately +14 seconds on a flat surface according to timegrapher measurement. (Slight variations may occur depending on the position). ・ Exterior: Although there are slight scratches and color fading on the edges of the case due to its age, it is a beautiful item overall with the black luster remaining and no major dents. ・ Crystal: No noticeable scratches, and visibility is clear. ・ Functions: Chronograph start, stop, and reset (zero return) all function correctly. The flyback function also operates smoothly. ● There may be scratches and stains that cannot be fully captured in the photos. Also, the evaluation of the item's condition is my subjective opinion, so there may be individual differences. Please refer to the description and photos for your consideration. ● Shipping will be done as quickly and carefully as possible.