INSTALL.more:
   Getting the NetBSD System on to Useful Media
     If you are using a UNIX-like system to write the floppy images to disks,
     you should use the dd command to copy the file system image(s) (.fs file)
     directly to the raw floppy disk.  It is suggested that you read the dd(1)
     manual page or ask your system administrator to determine the correct set
     of arguments to use; it will be slightly different from system to system,
     and a comprehensive list of the possibilities is beyond the scope of this
     document.

Gee, that's real fscking helpful.
Would it be that hard to include one example, perhaps on a NetBSD system?

# cd /mnt/cd0a/i386/installation/floppy/
# dd if=rescue-small.fs of=/dev/rfd0a bs=16k
74+1 records in
74+1 records out
1216512 bytes transferred in 53 secs (22953 bytes/sec)
# dd if=/dev/rfd0a bs=16k count=1 | file -
standard input:              x86 boot sector, BSD disklabel
Broken pipe
# fsck /dev/rfd0a
** /dev/rfd0a
BAD SUPER BLOCK: MAGIC NUMBER WRONG
fsck: /dev/rfd0a: Floating point exception

WTF?  Hmm, maybe it was blocking factor or lack of disklabel:

# disklabel -rw /dev/rfd0a floppy3
# dd if=rescue-small.fs of=/dev/rfd0a 
2376+0 records in
2376+0 records out
1216512 bytes transferred in 40 secs (30412 bytes/sec)
root@linkdead 1 bash# fsck /dev/rfd0a
** /dev/rfd0a
BAD SUPER BLOCK: MAGIC NUMBER WRONG
fsck: /dev/rfd0a: Floating point exception

*$&)T%&$*%&$&)!!!!

I am very annoyed.

I note these floppy images aren't disk-sized.

Am I correct in surmising that there is no manpage on the floppy diskette
driver?

Have the meanings of the letters at the end of fd0 changed or something?

What am I doing wrong?