Not sure if this is a double-size window or two separate windows, but "window" is one way at least of rendering this, being the little hole where your analog-face tells you the date or the larger hole where it tells you the date AND the day, etc.

Logo Watches with DATE-WINDOW. The Affordable Swatch Style Promotional Watch With Soft Plastic Strap, Swiss Parts Movement and DATE WINDOW at 3:00 Position. ...
www.fotowatch.com/datelogowatches_sp.htm

Movement. DAY WINDOW and Date Hand Automatically Advance After Midnight. Watch Signed Medana on the Dial, Case and Movement. Case ...
www.farfo.com/menswatches/Page7/medanacalender.html

android, usa, us, watch, watches, discount, discounted, sale ... by OKO Android USA Watch Co., classic ... steel case • Chronograph dials, DATE WINDOW with luminous ...
www.goldnsilverjewelry.com/03L2060M.html -

Tourbillon With Double Guichet Date

tourbillon automatic perpetual calendar split second chronograph minute repeater (the 1735). And now this year, the Leman Tourbillon with Double Guichet Date.

http://www.blancpain.com/e/best_articles/Short_Stories.html

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Note added at 32 mins (2005-03-07 17:57:50 GMT)
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http://www.watchpress.net/en/index_200309.html
Maurice Lacroix: Masterpiece Grand Guichet
05.09.2003/12.11 - Maurice Lacroix redonne à la date la place qui lui est due. Grâce au double guichet central du cadran en argent massif, la lecture des dizaines et des unités de la date est considérablement facilitée sur ce véritable chef-d’œuvre de la Masterpiece Collection de Maurice Lacroix baptisé Grand Guichet. Le fameux calibre automatique ML 58, finement ouvragé, anime ce modèle. Jour après jour, les échéances d’un agenda saturé rythment notre vie. ...

Maurice Lacroix: Masterpiece Grand Guichet
05.09.2003/12.13 - In their resolve to showcase the date, Maurice Lacroix watchmakers have designed the Masterpiece Grand Guichet to reveal the date’s two digits through a double central window in a dial made of solid silver. The model’s movement is the time-honored automatic ML 58 calibre recognized for its ultimate craftsmanship and performance. Appointments and deadlines fill our calendars and set the pace of our daily lives.

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Note added at 36 mins (2005-03-07 18:02:26 GMT)
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It is a luxury item,so I think it works well to keep the French (as you can see from the examples above)

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Note added at 38 mins (2005-03-07 18:03:58 GMT)
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double (central) window is the other option (but I\'d still keep the French)

guichet = dial aperture

www.solitaire.com.sg/magazine/story7.html - 19k

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Note added at 2 hrs 11 mins (2005-03-07 19:37:27 GMT)
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Sport Watches - Lycos Shopping has it!... This trendy mens sport watch features a sunray double dial with luminous hands and markers.
bizrate.lycos.com/buy/ products__at_id250351--12991-,cid--30020100,start--24.html - 116k

This double dial Lepine gold watch - No. 16.869 - included a minute ...
www.solitaire.com.sg/magazine/story7.html

Lycos - Seiko Gentlemans Arctura Chronograph Watch in Seiko ...Seiko Gentlemans Arctura Chronograph Watch buy from F [email protected] at ... Distinctive double-dial time display and chronograph features, date function. ...
shopping.lycos.co.uk/8652en16520703.html

developed the Big Date double window display for easy reading of the date (Patent No. CH 688 671).
http://www.pioner.com/ulysse/michel.html

Frankly, I would ask the watch company. It could be one of any of these. Couldn't they send you a photo?