Light blue never leaves steel in the 37 mm Royal Oak line. Audemars Piguet used it on the plain steel reference and on the diamond-set steel reference and in no gold configuration at either level of setting, and it appears in none of the fully gem-set versions. Of the five dials across the size it is also the palest, lighter than silver-toned and considerably lighter than grey or Bleu nuit nuage 50, which places it at the opposite end of the range from the anniversary signature colour while belonging to the same programme. In a plain case with no setting anywhere, that produces the brightest reference in the 37 mm line and the one furthest from the sports watch register the model comes from, since nothing on it is dark and nothing on it is warm.
The case is 37 mm across and 9.1 mm thick in stainless steel, with the plain octagonal bezel carrying the eight exposed hexagonal screws that have identified the Royal Oak since 1972, secured from beneath so the heads sit aligned. Brushed faces meet polished chamfers on every edge of case and bezel with the transition falling exactly on the line, and steel holds that boundary harder and cooler than gold. The dial is light blue with the Grande Tapisserie pattern, the larger of the two grids the collection uses. On a pale ground the tapisserie reads as fine relief rather than as shadow, since there is no dark field for the recesses to drop into, and the grid emerges only from the difference between the brushed square tops and their cut edges. That makes a pale dial the more demanding of the two to produce, because inconsistency in the cutting is visible where a dark dial would have hidden it. White gold applied hour-markers and Royal Oak hands sit above it. The bracelet is integrated steel, tapering from the case with the same alternation of surfaces, and closes on an AP folding clasp. Cool pale blue against cool steel gives the watch one temperature throughout, and because the dial sits so close to the case in lightness the boundary between them reads as a change of material rather than a change of colour, which is the opposite of what a dark dial in a steel case does.
The function set is hours, minutes, centre seconds and a date, the configuration the Royal Oak has carried since the original and the one the fully gem-set references in this size trade away. Centre seconds keeps all three hands on one axis and the date sits within the dial rather than at its edge. The applied markers do more work here than on the darker dials, since white gold hands over a pale blue field have limited contrast on their own and the markers supply the fixed points the eye needs. That is the standing cost of the palest dial in the range, and it is the one respect in which this reference asks more of the wearer than its siblings do. The date window helps here in a way it does not on the darker dials, because a printed numeral on a pale ground is the highest-contrast element on the whole surface.
The Royal Oak is the collection Audemars Piguet is built on, and the 37 mm anniversary references form a three-step ladder in setting. This reference is the base, unset at 9.1 mm. The diamond-set version holds the same height, because the bezel stones sit in metal that already existed. The fully gem-set version sets dial, bezel and bracelet in one coloured stone and reaches 10 mm, giving up the date and the applied markers in the process. Across the plain steel references the dials are silver-toned, Bleu nuit nuage 50, grey and light blue, with the last three continuing into standard production. The diamond-set steel references run light blue, Bleu nuit nuage 50 and grey; the diamond-set rose gold references run silver-toned, Bleu nuit nuage 50 and khaki green.
This reference suits a collector who wants a Royal Oak that reads light. Most of what the collection offers is dark-dialled or metal-dialled, and a pale blue in a plain steel case is a genuinely different object on the wrist, brighter and less formal than anything else in the size. It is also the most seasonal of the dials in the sense that pale blue behaves differently in summer light than in winter light, which some collectors value specifically and others avoid for the same reason. It appeals to someone who wants the anniversary programme without the anniversary colour, and to someone who has decided against gold and against setting and still wants the watch to have a point of view. The legibility trade is the price of that, and it is modest rather than serious, since the applied markers carry the dial even when the hands do not. The anniversary designation ties production to the occasion.
