How do I change the day language on a Seiko?

Two answers circulate. In the best-known forum thread, the owner of a Seiko showing Roman numerals was about to take the movement out of the case, and one reply suggested removing the dial. Another reply said to push the crown, which is right for one family of vintage calibers and wrong for almost every Seiko sold today. Neither quotes Seiko. On every bilingual Seiko we found a manual for, the language is chosen at the crown; what changes from caliber to caliber is which way you turn and whether you turn at all. We read six Seiko documents covering seven calibers, and the patent that describes how a two-language day wheel works.

Which way your crown turns, by caliber

Find the caliber number on the case back, the four characters before the hyphen (4R36, 7S26), as Seiko's general manual tells you to. Each row below quotes or closely paraphrases Seiko's own document.

The row that catches people is the 7S26. Its manual reverses the 4R36, so the SKX007 and the Seiko 5 Sports that replaced it set their days in opposite directions, and advice written for one is backwards on the other. The general manual avoids the problem by naming no direction: turn until the date moves, and the day is the other way.

Two common calibers have no day to change. The 4R35 shows the date only, and so does the NH35; the day-date version is the NH36, whose specification sheet calls it "Three Hands with Day & Date". Our page on the NH35 sets out the whole family.

Changing the language on a crown-set Seiko, step by step

This is the 4R36 and 7S26 procedure, and the order Seiko's general manual gives for every day-date watch it covers.

1. Check the time on the dial. If the hands are between 9:00 and 4:00 at night, run them forward to about 6:00 a.m. first. Seiko's general manual says: "first change the time to any time outside those hours, set the calendar and then reset the correct time."
2. Unlock the crown if it is a screw-down crown, as on the SKX007 and the Turtle: counterclockwise, the 7S26 manual's first step.
3. Pull the crown to the first click. On the 4R36 the seconds hand keeps running and "the accuracy of the watch is unimpaired".
4. Turn the crown in the date direction until yesterday's date appears. If today is the 5th, set 4. This is the quickset date.
5. Turn the crown in the day direction, one click at a time, until yesterday's day appears in the language you want. You will see the days alternate between the two languages. Stop on the right one: this is the step that sets the language.
6. Pull the crown to the second click and run the hands forward until the date changes. That is midnight, so the watch is now in the a.m. half of the day.
7. Keep going forward to the correct time. The date rolls to today at midnight and, on the 4R36, the day follows at about 4:00 a.m.
8. Push the crown home on a time signal, and screw it down if it screws.

Setting yesterday rather than today is what proves the hands are in the a.m. half. Get it wrong and, in the 4R36 manual's words, "the date will change at 12 o'clock noon, and the day of the week will change at around 4:00 p.m." When you bring the minute hand onto the time, Seiko's mechanical manuals say to "turn back the minute hand a little behind the desired time and then advance it"; our answer on turning the hands backwards explains why that is safe.

The push-crown Seikos: 7009 and 7019

On these two calibers the day is not on the turning crown at all. Seiko's general manual has a footnote under the day step: "For Cal. 7009 and 7019, push the crown back in to the normal position and then push it repeatedly to set the day." Each press flips the day wheel one position, through both languages, exactly as the clicks do on a turning crown.

That is the Watch Repair Talk thread from July 2015. The owner of a 7019-8180 wanted English, not Roman numerals, to be "dominant": the watch showed English at about midnight and switched to Roman numerals at about 2:30 a.m. The answer that worked: "7019 movement uses a push crown for day change. Keep clicking until desired english day is shown then leave it. English will now be dominant." Another member added that the crown must go "as far into the case as possible" to engage the lever, and may not if it is packed with dirt. The owner's reply: "just pushed in the crown & it flips the day." If a 7019 crown will not move inward at all, the push mechanism needs a watchmaker; the language is still not the fault.

Why the other language still shows overnight

Seiko's general manual answers the most common follow-up in one line: "When the day shifts automatically to the next day, the other language will temporarily appear." That is the 7019 owner's English between midnight and 2:30, and it is designed in.

Seiko does not publish drawings of its day wheels, but the mechanism is documented in a patent. US 3,683,614, "Day calendar timepiece with multiple language displays", was filed by Katsuhiko Komiyama of Tokyo on 21 July 1970, with Japanese priority from 23 July 1969, and granted on 15 August 1972. The printed patent names no assignee; a certificate of correction signed on 13 March 1973 adds it: Citizen Watch Co., Ltd.

The patent's disc carries "a alternately combined series of day calendar displays expressed in Japanese and English", fixed to a star wheel with seven teeth. The trick is the jumper, the spring that holds the star wheel still. A normal jumper has one point and parks the wheel once per tooth. Komiyama's has two, and "the circular pitch of these projections ... is one half the pitch of the star wheel teeth", so the wheel has two resting places per day, one per language. A pin on a wheel turning once in 24 hours pushes a 14-tooth driving wheel "two tooth pitches" a day, each tooth moving the star wheel half a step. So the day changes in two half-steps, and between them the window shows the other language.

The patent's first version switches language with a push button that advances the driving wheel "just one tooth", much as the 7019's push crown steps its wheel. Its second does it from the winding stem. And its claims generalise: n languages need "n successive jumper projections". The practical result is simple. Whichever language you leave the wheel on shows all day; the other appears only between the two overnight steps.

The hours not to set it

Every Seiko day-date owner's manual we read prints 9:00 p.m. to 4:00 a.m. That is three hours longer than the date-only 4R35's 9:00 p.m. to 1:00 a.m. in the same booklet, because on the 4R36 "the date changes around 12 o'clock midnight, and the day around 4:00 a.m." The current 4R manual (JSY4RCC2-A2403) says setting then "may cause problems such as the date or the day of the week failing to change the next day or may cause damage". The older booklet warned about the date; the current one, and the 7S26 manual, name the day too.

A 2023 thread shows what that looks like. A new Seiko SUR495's day wheel "stopped in between a day" while its owner scrolled through the days. The first reply asked what time the hands were showing and quoted Seiko's general manual. The owner, the same evening: "This fixed the problem. Didn't know how to set it I guess." Our answer on when it is unsafe to change the date explains what is engaged inside during those hours, and the page on a date that will not change at midnight covers a calendar that has already been forced.

If the wrong language keeps coming back

• Your language shows at night and the other one all day. You stopped on the wrong half. Go back to the first click and step the day on until your language shows; the date does not need touching.
• One click brings the next day, not the same day in your language. Keep clicking. The crown steps the day wheel one way only, and fourteen clicks bring a two-language wheel all the way round.
• Every click shows a new day in the same language. The wheel is single-language and no setting will change it. The disc sits under the dial, so a different language means a different disc, fitted by a watchmaker with the hands and dial off.
• The language is right but the day flips in the afternoon. The watch is twelve hours out. Set it again from step 1.

A day wheel that does not match the rest of the watch is also worth a look on a secondhand Seiko, as our SKX007 page notes and our guide to spotting a fake explains.

When this answer stops applying

• Your manual says otherwise. The table covers documents read on 27 October 2026. Seiko's manual for your caliber beats it.
• The movement is not a Seiko. A Citizen, Miyota or Swiss day-date follows its own manual, and the direction may differ.
• The crown does nothing at the first click. That is a fault in the keyless work, not a language problem. Our guide to setting and adjusting your watch covers crown positions.