It's reasonably common for people to buy larger trowels and to grind
them down to a more reasonable size, and even build in a left or right
hand bias.
In Japan the weapon of choice is a stainless steel gardening hand
shovel, with a shallow blade about 15 cm long, and 10 cm wide. This is
sharpened on a whetstone until it is literally razor sharp [a daily job
that is allocated to one person]. These work brilliantly in high clay
content soils because they can shave off a mm thick layer at a time
without any smear or adhesion, leaving the most beautiful exposure.
Whether this is an indigenous adaptation or accommodation of [apparent]
lack of traditional western trowels I can't say.
There is an interesting use of shallow rubber spoil buckets, which look
like the ?goofas commonly used on Middle Eastern digs. A number of
early Japanese archaeologists worked with Flinders Petrie and may have
picked up the use of them from his Egyptian digs.
Denis Gojak