diff --git a/README.md b/README.md
index d832ccd8..b569dd69 100644
--- a/README.md
+++ b/README.md
@@ -103,6 +103,7 @@ people who've had it work).
 | [Brother 120kB](doc/disk-brother.md)      |  🦄   |   🦄   |                                     |
 | [Brother 240kB](doc/disk-brother.md)      |  🦄   |   🦄   |                                     |
 | [Brother FB-100](doc/disk-fb100.md)       |  🦖   |        | Tandy Model 100, Husky Hunter, knitting machines |
+| [Elektronika BK](doc/disk-bd.md)          |  🦄   |   🦄   | Soviet Union PDP-11 clone           |
 | [Macintosh 400kB/800kB](doc/disk-macintosh.md)  |  🦄   |   🦄   |                                     |
 | [NEC PC-98](doc/disk-ibm.md)              |  🦄   |   🦄   | trimode drive not required          |
 | [Sharp X68000](doc/disk-ibm.md)           |  🦄   |   🦄   |                                     |
diff --git a/doc/disk-bk.md b/doc/disk-bk.md
new file mode 100644
index 00000000..aa6d7d3d
--- /dev/null
+++ b/doc/disk-bk.md
@@ -0,0 +1,37 @@
+Disk: Elektronica BK
+====================
+
+The BK (an abbreviation for бытовой компьютер --- 'home computer' in Russian)
+is a Soviet era personal computer from Elektronika based on a PDP-11
+single-chip processor. It was the _only_ official, government approved home
+computer in mass production at the time.
+
+It got a floppy interface in 1989 when the 128kB BK-0011 was released. This
+used a relatively normal double-sided IBM scheme format with 80 sectors and ten
+sectors per track, resulting in 800kB disks. The format is, in fact, identical
+to the Atari ST 800kB format. Either 5.25" or 3.5" drives were used depending
+on what was available at the time, with the same format on both.
+
+Reading disks
+-------------
+
+Just do:
+
+```
+fluxengine read bk800 -o bk800.img
+```
+
+You should end up with an `bk800.img` containing all the sectors concatenated
+one after the other in CHS order. This will work on both 5.25" and 3.5" drives.
+
+Writing disks
+-------------
+
+Just do:
+
+```
+fluxengine write bk800 -i bk800.img
+```
+
+This will write the disk image to either a 5.25" or 3.5" drive.
+
diff --git a/mkninja.sh b/mkninja.sh
index a0dd27c3..0b29a17e 100644
--- a/mkninja.sh
+++ b/mkninja.sh
@@ -523,6 +523,7 @@ FORMATS="\
     ibm180 \
     ibm360 \
     ibm720 \
+    bk800 \
     mac400 \
     mac800 \
     micropolis143 \
@@ -664,6 +665,7 @@ encodedecodetest atarist720
 encodedecodetest atarist740
 encodedecodetest atarist800
 encodedecodetest atarist820
+encodedecodetest bk800
 encodedecodetest brother120
 encodedecodetest brother240
 encodedecodetest commodore1541 scripts/commodore1541_test.textpb
diff --git a/src/formats/bk800.textpb b/src/formats/bk800.textpb
new file mode 100644
index 00000000..b72a6090
--- /dev/null
+++ b/src/formats/bk800.textpb
@@ -0,0 +1,68 @@
+comment: 'BK 800kB 5.25"/3.5" 80-track 10-sector DSDD'
+
+image_reader {
+	filename: "bk800.img"
+	img {
+		tracks: 80
+		sides: 2
+		trackdata {
+			sector_size: 512
+			sector_range {
+				start_sector: 1
+				sector_count: 10
+			}
+		}
+	}
+}
+
+image_writer {
+	filename: "bk800.img"
+	img {}
+}
+
+encoder {
+	ibm {
+		trackdata {
+			target_rotational_period_ms: 200
+			target_clock_period_us: 4.0
+			emit_iam: false
+			gap0: 80
+			gap2: 22
+			gap3: 34
+			sectors {
+				sector: 1
+				sector: 2
+				sector: 3
+				sector: 4
+				sector: 5
+				sector: 6
+				sector: 7
+				sector: 8
+				sector: 9
+				sector: 10
+			}
+		}
+	}
+}
+
+decoder {
+	ibm {
+		trackdata {
+			sector_range {
+				min_sector: 1
+				max_sector: 10
+			}
+		}
+	}
+}
+
+tracks {
+	start: 0
+	end: 79
+}
+
+heads {
+	start: 0
+	end: 1
+}
+