Modified Hiragana

Besides the 46 basic Hiragana, some modified Hiragana are also used in Japanese.

Modified Hiragana 1
The sounds of Hiragana with two dots, and a little circle are as follows;

Syllables with voiced consonants (like English g, z, d, and b) are represented by adding two dots at the upper right-hand corner of the corresponding basic Hiragana. For historical reasons, ba-bi-bu-be-bo are related to ha-hi-hu-he-ho.
Syllables pa-pi-pu-pe-po are represented by adding a little circle at the upper right-hand corner of the corresponding basic Hiragana; ha-hi-hu-he-ho. For historical reasons, pa-pi-pu-pe-po are related to ha-hi-hu-he-ho.

C / V	a	i	u	e	o
g
	ga	gi	gu	ge	go
z
	za	ji	zu	ze	zo
d
	da	ji	zu	de	do
b
	ba	bi	bu	be	bo
p
	pa	pi	pu	pe	po

The pronunciation of "ぢ" and "づ" is the same as "じ" and "ず" respectively.
じ and ず are more frequently used than ぢ and づ.

Modified Hiragana 2
The sounds of Hiragana with palatalized consonants are as follows;

Syllables containing palatalized consonants such as kya, hyu, or sho are represented by the combination of basic Hiragana of the i column and small-sized ya, yu, and yo. These small ya, yu, and yo should be placed in the lower left-hand side of the normal size when they are written horizontally.
These syllables are written by the combination of two Hiragana, but they should be pronounced as one sound; they have same length as normal syllables.

C / V	a	u	o
ky
	kya	kyu	kyo
sy(sh)
	sha	shu	sho
ty(ch)
	cha	chu	cho
ny
	nya	nyu	nyo
hy
	hya	hyu	hyo
my
	mya	myu	myo
ry
	rya	ryu	ryo
gy
	gya	gyu	gyo
jy(j)
	ja	ju	jo
by
	bya	byu	byo
py
	pya	pyu	pyo