The Bis Key
The "Bis" key on the saxophone is located between the first finger "b" key and the second finger "a" key in the upper part of the instrument. The Bis key can be easily identified because it has a disc-shaped pearl that is smaller than those of the "b" and "a" keys. In most cases, the Bis key is closed using the first finger while that same finger is also pressing the "b" key. By simultaneously pressing both the "b" key and the Bis key, the pitch "Bb" is produced.
WHY IS IT CALLED "BIS"
Bis is a French term that can mean several things:
"again," "repeat," "encore" or "double" (as in something that is duplicated) and more!
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These definitions make sense for the saxophone, because the Bis key is a redundant (or alternate) key for playing the note Bb. The saxophone also has a side Bb key, and that side Bb key was included by Adolph Sax in his original 1846 design for the saxophone. The Bis key was added in 1887 as a new improvement to the saxophone, and was devised by the Evette & Schaefer Company. When first introduced, the Bis key was considered an "extra" Bb key.
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Here is a link to the original 1846 patent by Adolph Sax.
Here is very beautiful (and detailed) set of photos from an original 1861 saxophone that was made in Paris by Adolph Sax:
https://www.getasax.com/product/adolphe-sax-alto-saxophone-from-1861-rare-large-bell-plays/
Here is another very beautiful (and detailed) set of photos from a saxophone that was made in Paris between 1872 and 1878 by Francois Millereau. This instrument is considered a very close copy of Adolph Sax's earliest instruments:
The reader will note that the original saxes had very few side keys, and that the octave vents were opened by two separate levers that must be deliberately controlled by the performer.
I spent several summers teaching in Paris for the University of Washington overseas prgram. Just for fun, here is a photo of me (in Paris) playing an original Adolph Sax soprano saxophone that was made in 1858. ​
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More about the word "Bis"
According to French.about.com:
https://www.thoughtco.com/bis-vocabulary-1371638
Bis (adverb)
The French pronunciation is "beess" while English speakers generally say "biss" (rhymes with "kiss")
In music, it means repeat, again, or encore:
- "A la fin du concert, le groupe a joué deux bis."
(At the end of the concert, the group played two encores.)
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In a street address, it means "plus ½" (or it can mean the addition of the suffix "a" following a house number)
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- "Elle habite 43 bis Boulevard Saint-Michelle"
(She lives at 43½ Saint Michelle Boulevard -- or 43a Saint Michelle Boulevard)
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The "double" or "repeat" definition makes sense, as the bis key is a redundant (alternate) key for playing the note Bb.
The "address" definition also makes sense for the saxophone, because the bis key lowers the note B by 1/2 a step.
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Some other meanings:
bis (adj) = grayish-brown;
un itinéraire bis - detour, or diversion in the road
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Here is an official citation for when this sort of info needs some academic documentation:
Team, ThoughtCo. "Bis or Encore in French." ThoughtCo, Jun. 26, 2024, thoughtco.com/bis-vocabulary-1371638.