Citizen 9051 User manual

INSTRUCTION MANUAL

1
English
To check the movement number
A case number—4 alphanumeric characters and 6 or
more alphanumeric characters—is engraved on the
case back. (Figure on the right)
The first 4 characters of the case number represent
the movement number of the watch. In the example
on the right, “ ” is the movement number.
Thank you for your purchase of this Citizen watch.
Before using the watch, read this instruction manual carefully to ensure
correct use.
After reading the manual, store it in a safe place for future reference.
Be sure to visit the Citizen website at https://www.citizenwatch-global.com/ .
Here you will find a variety of information such as electronic setting guides,
answers to frequently asked questions, Eco-Drive recharging information and
more.
Engraving position example
The engraving position may
differ depending on watch
model.

2
Safety precautions — IMPORTANT
This manual contains instructions that should be strictly followed at all times
not only for optimal use, but to prevent any injuries to yourself, other persons
or property. We encourage you to read the entire booklet (especially
20
-
29
) and
understand the meaning of the following symbols:
■ Safety advisories are categorized and depicted in this manual as follows:
DANGER
Highly likely to cause death or serious injury
WARNING
Can cause serious injury or death
CAUTION
Can or will cause minor or moderate injury or damage

3
English
■ Important instructions are categorized and depicted in this manual as follows:
(Following symbols are examples of Pictograms.)
Warning (caution) symbol followed by prohibited matters.
Warning (caution) symbol followed by instructions that should be
followed or precautions that should be observed.
Safety precautions

4
Safety precautions
Precautions to be taken when diving
PROHIBITED Do not use this watch while diving when...
CAUTION Diving with the watch
• Do not use your watch while diving when the watch stops or exhibits any
abnormal operation.
• Persons using the diver’s watch are strongly recommended to receive proper
instruction and training pertaining to diving and observe those rules at all times.
• Please use this watch properly only after you fully understand the operating
procedures and cautions.
Using this watch other than as indicated in this instruction manual may result in
failure of the watch to function properly.
• Check the water-resistant indications on the watch face or the case back. Never
dive beyond the indicated depth.

5
English
Safety precautions
CAUTION Before diving
CAUTION During diving
CAUTION After diving
• Check items below before diving
- Make sure that the mainspring is fully wounded
- Make sure that the watch is running correctly (check the movements of the
time/calendar/second hand)
- Make sure that the crown is fully pushed in and its screw is tighten firmly
- Make sure that the band is firmly anchored to the watch body.
- Make sure that there are no cracks or other damage to the watch band or the
glass face.
- Make sure that the register ring rotates properly.
• Do not operate the crown in the water. Operating any of them in water may cause
trouble including deterioration of water resistance.
• Be careful not to hit the watch against hard objects such as equipment or rocks.
• Check to see if the crown is pushed in and locked before removing the sea water,
dirt, and sand attached to the watch with fresh water. Then, wipe the fresh water.

6
CONTENTS
Characteristics of Mechanical watches .......................
7
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Before using this watch .................................
10
Component identification ...............................
13
Mainspring ............................................
14
Adjusting the time and calendar ..........................
16
Using the rotating bezel .................................
18
Water resistance .......................................
20
Precautionary items and usage limitations.................
22
Specifications ..........................................
30

7
English
Characteristics of Mechanical watches
About time accuracy of mechanical watches
The time accuracy described on this instruction manual is the static accuracy
at normal temperature. The accuracy of mechanical watches may get out of the
described range depending on the following three usage conditions or other reasons.
• Winding amount of the mainspring
• Attitude
• Usage environment (temperature, magnetism, impact, etc.)
Winding amount of the mainspring
Mechanical watches keep accuracy
most stably when the mainspring is
sufficiently wound.
Attitude
Accuracy of mechanical watches varies
affected by gravity. The accuracy varies
as the result that may take various
attitude while worn and gravitate to a
different direction every moment.

8
Usage environment (temperature, magnetism, impact, etc.)
• Metal parts are used for the part for keeping accuracy in mechanical watch. The
accuracy varies affected by their thermal expansion and contraction.
• Metal parts are used in mechanical watches. Magnetism affects them and
accuracy of the watches in consequence. Do not bring them close to things which
have or generate strong magnetism.
• Strong shocks may also affect the accuracy.
Maintenance
Mechanical watches may become inaccurate due to insufficient lubrication or worn
parts. Have the watch disassembled and cleaned (overhaul) every 2-3 years (charge
basis). It may be difficult to restore the watch from degradation after long-term use
to its initial performance even after repairs.
Characteristics of Mechanical watches

9
English
Features
■
Water-resistant to 200m
• This watch is a SCUBA diver’s watch (water-resistant to 200m). You can use it
for SCUBA diving with air tanks, but must not be used in a helium-enriched
atmosphere (e.g. saturation diving).
■
Automatic winding movement
• A automatic winding movement is employed in which the watch mainspring
is wound automatically by movement of the hand when worn, and the force of
the mainspring is then used to drive the movement (watch).
[Automatic winding]
When worn on the wrist, the normal movement of the arm will wind the mainspring.
[Manual winding]
Rotate the crown clockwise while it is in position to wind the mainspring.