Per Hironori's website:

"Matchbox Dropping Rule Sep.19 2000

1. At first hang 2 hard sponge matchbox size targets 3.5 X 5.5 cm
(1.38 X 2.17 in) by fishing line in right and left on the sponge mat
(Note: Target backstop). Total matchbox targets are 10. The hight
is 160 cm(4.8 feets).
Shooting line is 10 meter(11 yard) away from target.
2. Make a ring by the line and hang it by U type pin on the sponge
mat.
3. The dart which scratched the target and turned over the match is
ineffective.
4. When the dart which rebounced after hitting target is effective.
5. When dart hit the target but target did not drop.The dart is
effective.
6. When the dart rebounced and it was unclear whether it hit the
target or not.
The second shooting is counted.
7. Entrant can chose the first matchbox which he shoots.
8. Entrant can aim the next matchbox after the first matchbox was
dropped.
9. When dart enclosed the matchbox target and prevents dropping.,
player can pull darts off with approval of marker.
10. Entrant can stop shooting anytime if he gave up.
Entrant must stop shooting when time passed over limitted time
(40 minuites)
11. Entrant can clean the inside of pipe whenever he wants.
12. After marker recognized the number of darts,entrant can pull
darts
off from sponge mat.
13. They must follw to the point game rule in other problems

International Fukiyado Association IFA, Japan Branch
H.Higuchi �@mailto: info@..."

NOTE: I have tried dropping these with the standard .50 cal. target
darts, and it doesn't always work. In Japan, they use a film cone
(like transparency film stock) dart - made similar to Charlie
Shapiro's Paper Darts.

Details on how to "roll your own", and pictures of a completed dart
are available on the NSBA website, on the dartmaking.htm page.
(All IFA internationally certified instructors, and all NSBA
nationally certified instructors are required to make a film cone
dart of this type as part of their requirements for instructor
certification.)

It is referred to as a "matchbox", because of it's similar size and
shape to the small pocket sized wood "strike-on-the-box" stick
matches, used before the paper matchbooks were developed (still
available in some locations).

The sponge foam itself appears to be similar in composition and
density to the canned insulation foam available from hardware
stores. The ones Hironori gave me have a "finished" colored side
(red or blue), making me think it was cut from an insultation board.
The closest to this that we have in the USA that I could find would
be in the insulation aisle of your hardware superstores (Home Depot,
Lowes, etc.) - the plastic insulation board - cut it to fit as
indicated above. I use 2 pushpins - one on an end loop, wrapped
around the metal of the pin - this holds the "target" in place - the
other one, suspend a bight (look up knot-tying terminology if you
don't know what this means) of the monofilament line between the
plastic of the pushpin, and the backstop material - but NOT
encircling the metal pin - rather beneath it. The impact and
additional weight of the dart added to the weight of the
monofilament and foam matchbox, should be sufficient to pull the
monofilament out from between the face of the backstop and the
plastic back of the pushpin, causing it to drop. This is key to
Hironori's "blowgun tricks"! The weight of the dropping dart and
matchbox pull a "7" or "L" shaped lever out of a loop (developed by
Hironori), which in turn is connected (ala "Rube Goldberg") to
another deice / string / etc. - causing a wine bottle cork to be
pulled out, or a paper mache ball to crack open, etc., etc. for some
great theatrics.