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parts; 
•
protection from scatterings; 
countermeasures against broken fragments 
of stones or mechanical parts; 
•
battery; protection from electrolyte 
solution, etc.; 
•
stability; stability of the machine on a 
slope; 
•
lighting; 
•
safety mark; 
•
ease of handling; 
•
others, limitation of a hand tractor, etc. 
Test results
- After completing the test 
procedure, IAM-BRAIN assesses whether the 
machine conforms to the test standards, 
notifies the applicants of the test results and 
reports them to the Ministry of Agriculture, 
Forestry and Fisheries. The Ministry of 
Agriculture, Forestry and Fisheries publishes 
the model name of the approved machine and 

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its approval number, and notifies this 
information to the Prefectures of Japan and to 
the institutions concerned (
Table 7
). 
3. Transition of structure and performance 
on tractors
The Official tests have seen changes in the 
structure and working performance of 
machines over the years (
Table 8
). Some 
noteworthy points are detailed below. 
3.1 Structure 
Improvements in waterproofing 
- About 24% 
of the tractors rejected by the National test in 
the 10 years since 1974 failed due to water 
penetration into the machine. The principal 
causes were insufficient waterproofing 
performance of oil seals and damage to the oil 
seals or O-rings during assembly. Nowadays, 
the performance of oil seals has been 
improved and the manufacturing process is 
fully managed, resulting in a marked 
reduction of problems with the waterproofing 
test. 
Improvements in ease of handling
- In the 
National test, the controllability and visibility 
of tractors must ascertained in actual 
operation. Ease of handling, visibility and 
comfort have all been improved today. 
Foot plate (Driver floor space)
- In older 
tractor models, the transmission case and its 
lever were generally located in front of the 
driver’s seat, and the operator had to step 
across this part when driving. So there was 
little space around the foot, making it difficult 
to get on and off. In the early 1980s, tractors 
were developed which had a flat driver floor 
space, making it easier to get on and off and 
improving comfort. Most domestically 
manufactured tractors now have a flat floor 
with the shift levers set at the side of the 
tractor. 
Power shift transmission
- The development 
of power shift transmissions with hydraulic 
clutches now enables operators to shift gears 
without having to operate the main clutch 
pedal. Moreover, a concentrated shift lever 
which has the function of a sub and main shift 
lever has been developed, enabling the 
operator to shift gear with one lever. 
Improvements in the handling of implements
- 
A device which keeps implements horizontal 
when the vehicle tilts, and which keeps 
implements at an angle had been developed. 
Moreover, the “quick coupler” device which 
facilitates the attachment of implements is 
frequently used by farmers. 
Improvements in manoeuvrability of levers 
and pedals
- Most tractors are now equipped 
with power steering devices. Consequently, 
the force necessary to operate a clutch pedal, a 
service brake pedal or the shift levers has 
been reduced. 
Safety equipment
- Most domestically 
manufactured tractors are equipped with 
safety guards for moving parts and hot areas, 
covers on both sides of the engine, around the 
exhaust pipe, etc.