No. 46: IN FREUNDSCHAFT (In Friendship)
for Various Solo Melody Instruments
1977 [ca. 15']

“Clear differentiation, relation to a common and constant center, exchange, approaching one another, movement of lively ascending elements towards the end of the formula: IN FRIENDSHIP.” 
- Stockhausen

     IN FREUNDSCHAFT was written as a clarinet solo for (and dedicated to) woodwind player Suzanne Stephens for her birthday and was first premiered by her in 1978, though a flute version was performed earlier during Stephens' actual birthday celebration.  In the following years, Stockhausen composed versions for many more instruments, including recorder, oboe, bassoon (w. teddy bear costume), basset horn, bass clarinet, horn, contra-bass, soprano saxophone, tuba, cello, violin, viola, trumpet, and trombone.  For this reason, it's probably one of the most performed of Stockhausen's pieces, at least for solo recitals.
The bottom staff is a retrograde inversion
(backwards and upside-down) of the top staff.
The sections engage in a layered dialogue.
(from cover to Stockhausen Edition CD 102 - IN FREUNDSCHAFT )

Form Scheme
     As in INORI, this work is rooted in a formula theme-melody, which Stockhausen divides into 5 sections separated by rests.  The formula gets a "mirror form" when it is flipped and the 5 sections reversed.  This is illustrated in the covers to the IN FREUNDSCHAFT Stockhausen Edition CDs 101 and 102. 

     In the piece, the formula in its basic form is first played, ending with a long, slow trill.  This trill becomes the "center line" of the piece and returns pretty frequently.  After this, the formula and its mirror-version are played in 2 different registers at the same time (the section phrases take turns being played by the soloist).  The fragments of the mirror form start out loud, fast and low pitched, while the ones for the original formula are quieter, slower and high pitched.  This poly-layered solo line is repeated 6 more times, with each layer moving closer and closer in pitch transposition, duration and texture.  The "limbs" (sections) also slowly switch places during this progression.  Finally a "synthesis of the two layers" is reached in the coda.  Actually the rate of change is not exactly constant, there are some pretty dramatic jumps after the 3rd Cycle.  This cyclic melding of layers is interrupted by "explosions" (cadenzas) after the 3rd and 6th cycles.  These 2 events function somewhat like "inserts" to the formal structure.  Aside from the melodic restructuring, this piece features important dynamic shapes and tempo changes, as well as very specific trill articulations.  Stockhausen has written an excellent analysis of this piece called "The Art, To Listen", which details all of the colorful details of this form structure realization and comes with the score (or can be ordered separately).

Clarinet version by Suzanne Stephens from Stockhausen Edition 27:

(basic formula)
(+ 7 secs. silence at beginning)
Cycle I (formula & mirror) 0:53
Cycle II 0:56
Cycle III  0:57
1st Explosion:
Cycle IV  0:53
Cycle V  1:04
Cycle VI 1:46
2nd Explosion (Trills):
"vehement, happy"
Cycle VII  1:11
Synthesis Of 
The Two Layers 

Page 1, basic formula in first line, followed by slow trill (with foreshadowing of layers).
Cycle I begins in line 7.
Synthesis of the Two Layers after the double bar (ending)
Live Performance
     A live performance by a reed instrument performer has the added benefit of illustrating the different registral layers.  When playing a phrase from the basic formula, the horn is pointed to the player's left.  When a mirror section is performed, the horn is pointed to the right.  The center line trills are played while pointing forward.  High and low notes are represented by pointing up and down.

Sound Impressions
     IN FREUNDSCHAFT is great fun, and full of drama due to the constantly intertwining formula layers.  It feels a bit like hearing a person with 3 split personalities having a conversation with his alter egos.  Live, the motions of the soloist are entertaining as well.  It's not critical to follow the layers develop, thematic motion is naturally built into the piece, but it's an added dimension to appreciate and prepares one for Stockhausen's further developments in this concept in later pieces.  Also it's a very adaptable piece, theoretically (and unofficially, of course) it could be played on any melody instrument, including theremin. 

Samples, track listings and CD ordering:
Purchase the Scores (15 different instrumentations)
"The Art, to Listen", Stockhausen Essay on IN FREUNDSCHAFT
Wiki Article
EXCELLENT Analysis by Richard Faria (PDF)
The Saxophone Works of Karlheinz Stockhausen (Bunt, PDF thesis)
Sonoloco Review
Clarinet Version, Youtube clip
Soprano Saxophone Version, Live
Bassoon with Bear Costume, Live
Oboe Version, Live
Violin Version with adlibbed action-drawing, live