Seiko SQ, Ref. 5H23-6230, Cal. 5H23, Men’s Quartz, 1987

Seiko SQ 1987 — First impression

This Seiko SQ is a compact and distinctive Japanese quartz analog watch from 1987, built around clarity, daily practicality and a very recognizable late-1980s dial layout. The watch measures 33 mm across the stainless steel case, with a 39 mm lug to lug length and 18 mm lug width, giving it an easy vintage wrist presence. The dial is the central point of interest: a grey surface with oversized blue minute numerals, a diagonal blue-grey band and a day-date display at three o’clock. The weekday wheel is shown in kanji, adding strong Japanese character and making the watch more visually memorable than a plain quartz dress model. It is fitted to a new black NATO strap, which gives the watch a practical, casual and ready-to-wear presentation.

Seiko SQ - Grey Minute-Track Dial

The dial has a soft grey tone with light age marks and a utilitarian minute-focused design. Large blue numerals mark the five-minute intervals around the dial, creating a layout that feels more graphic and modern than a traditional baton-marker dress watch. A diagonal blue-grey stripe runs across the dial toward the day-date aperture, adding depth and a distinctly 1980s design accent. The Seiko logo and Quartz text are printed on the left side, while the SQ emblem sits in the lower half of the dial. Small applied dot markers and the outer minute track support legibility. The overall surface shows modest vintage patina, but the design remains clear and attractive.

Hands

The hands are white and blue outlined baton-style hands, well matched to the blue minute numerals and the cooler grey dial. The hour and minute hands are bold enough to read easily, while the central seconds hand is slim and practical. Their shape reinforces the functional nature of the watch: this is a timepiece designed for quick reading, not for heavy decoration. The hands sit cleanly over the diagonal dial band and preserve good contrast against the grey background. Together with the kanji day-date display, they give the watch a strong Japanese quartz identity.

Seiko SQ 5H23-6230 - Stainless Steel Case

The case is stainless steel and has a compact round form with protective shaping around the crown area. The surfaces show visible scratches and wear consistent with a used vintage watch, but the case retains a clean, practical appearance. The polished bezel frames the dial, while the small lugs and curved case profile help the watch sit comfortably on the wrist. At 33 mm, the watch is modest by modern standards, yet the graphic dial makes it wear with more presence than the measurement alone suggests. The reference 5H23-6230 connects the watch to Seiko’s quartz production of the period, where practical case construction, reliable movements and accessible design were central strengths.

Crown

The crown is positioned at three o’clock and sits partly within the protective case shape. It has a ridged stainless steel profile and appears unsigned in the supplied image. On a quartz analog watch, the crown is mainly used for setting the time and calendar rather than daily winding, but its placement and guarded design support the watch’s everyday character. The small side detail near the crown gives the case a more technical appearance and fits well with the practical SQ design language.

Seiko SQ New NATO Strap

The watch is fitted with a new black NATO strap. The strap is not presented as original, but it suits the watch very well because it emphasizes the practical, casual side of the design. Black nylon also contrasts strongly with the grey dial and stainless steel case, keeping the watch visually clean and modern. The 18 mm lug width is convenient for future strap changes, allowing the next owner to keep the NATO look or move to leather if a more formal presentation is desired. The strap makes the watch immediately wearable while preserving the originality of the watch components themselves.

Seiko SQ 1987 - Japanese Quartz Analog 5H23 with Day-Date Display

The movement is listed as Seiko Cal. 5H23, a Japanese quartz analog movement with day-date functionality. No unsupported technical specifications are added. The key appeal here is practical precision timekeeping and the convenience of a calendar display. The dial shows the date and a kanji weekday indication, which is one of the most attractive details of this example. The service status is recorded as In Service, and the operational status is recorded as Yes. As a vintage quartz watch, this Seiko SQ represents a period when Japanese horology heritage was strongly connected to reliability, accuracy and functional design. More examples from the brand can be found in our Seiko vintage watches collection with 1987 SQ quartz character.

Heritage of the Seiko SQ in 1980s Japanese Quartz Design

The Seiko SQ line belongs to the era when quartz technology had become fully established as a serious everyday standard. By the 1980s, Seiko was producing reliable analog quartz watches that combined accuracy with a broad range of design experiments. This example is especially interesting because it avoids a conservative dial and instead uses large minute numerals, a diagonal graphic band and a kanji day display. These details make the watch feel authentically Japanese and clearly connected to its decade. It is not a luxury watch in the traditional Swiss sense; it is a collectible everyday timepiece with strong design identity, useful calendar function and real period charm. You can compare it with other quartz analog vintage watches with Japanese day-date style.

12-Month Warranty, Worldwide Shipping Condition, Originality

This Seiko SQ is recorded as an all original watch with a new NATO strap. In practical terms, the watch components are treated as original, while the strap is a fresh replacement selected for comfort and daily use. The grey dial shows light vintage patina and small marks, the stainless steel case shows normal scratches and age-related wear, and the overall condition is best understood as honest vintage condition rather than modern cosmetic perfection. Box and papers are not included. The watch is operational and comes with a 12-month movement warranty. Vintage Watch Studio ships worldwide and describes each watch with attention to condition, originality and buyer confidence. For the right collector, the appeal is direct: a 1987 Seiko SQ Ref. 5H23-6230 with Cal. 5H23, kanji day-date display, grey graphic dial, stainless steel case and new black NATO strap.