The Pesantren Darul Ulum is located in the eastern part of Jombang. It is around three kilometres from the centre of the city of Jombang. This pesantren is classified as modern. It has around 3,600 santri living in its dormitories. The Pesantren Darul Ulum runs a modern school system from primary school to university. It has a rather large university, that is the Universitas Darul Ulum, one of the three tertiary educational institutions available in Jombang. In addition to its modern system of education, it also runs its traditional system. The santri in this pesantren go to school or university during the day and attend the pengajian (religious teaching) in the evening.

The Pesantren Darul Ulum was established in 1885. This is the formal date acknowledged by the kiai currently leading this pesantren. The pesantren was established by a young kiai, Tamim, who came from Madura island. Since Tamim started teaching Islam (pengajian) among his neighbours soon after he arrived in Rejoso village, the exact date of the establishment of his pesantren could be earlier than the formal date. His kindness and knowledge of Islam had already made him a public figure in his society.

Following Tamim was Muhammad Djuremi, a young Muslim who came from Demak, the northern region of Central Java. Muhammad Djuremi, who by that time had followed his father to live in Pare (around 30 kilometres from Jombang), was interested in Tamim's activities because Tamim was widely known as an expert on Islam and on ilmu kanuragan (lit. supernatural power). Muhammad Djuremi became Tamim's close santri and helped him to teach other junior santri in Tamim's pesantren. Kiai Tamim, as people called him a few years later, married Muhammad Djuremi to his daughter. Muhammad Djuremi later changed his name to Muhammad Kholil after he returned from the hajj. According to Sukamto (1992) the number of santri studying in Kiai Tamim's pesantren after Muhammad Djuremi involved himself in its teaching was around 200. Kiai Kholil, as people called Muhammad Djuremi later, succeeded Kiai Tamim as leader of the Pesantren Darul Ulum after the latter died in 1930.

In contrast to his father-in-law, Kiai Kholil involved himself in tarekat activities. He took bai‘a (lit. allegiance) and followed the Qadiriyah Wa Naqsyabandiyah order (tarekat). He was then regarded as one link in the chain of the murshidship of the Qadiriyah Wa Naqsyabandiyah order (see discussion on this sufi order in Chapter III). His formal leadership of the pesantren lasted for about seven years. After his death, the leadership of the Pesantren Darul Ulum was assumed by (Muhammad) Romly Tamim, one of the four children of Kiai Tamim. Two years later, Kiai Kholil's son (Kiai Dahlan Kholil) returned from Mecca, and helped Romly Tamim in managing the Pesantren Darul Ulum.

The period during which Kiai Romly Tamim and Kiai Dahlan Kholil led the Pesantren Darul Ulum was a period of development. Both of these kiai, assisted by Kiai Ma‘shum Kholil, contributed significantly to this development. The three kiai introduced madrasah ibtidaiyah (Islamic primary school) and mu‘allimin (teacher school) in 1952 and 1958. The mu‘allimin is similar to a high school. It then changed to SMP (junior high school) and SMA (senior high school) in 1964. The formation of these schools aimed to introduce a new system of learning in the  pesantren. It can be suggested that the leadership of these three kiai created a favourable situation for the development of the pesantren they were managing. All three kiai spent some of their time in Mecca studying Islam. The impression they gained from the pattern of teaching in the Darul Ulum Addiniyyah in Mecca, an Islamic school in which they took Islamic studies, inspired them to make a breakthrough in regard to the system of education in their own pesantren. Kiai Dahlan Kholil, who spent around thirteen years studying in this Islamic school, proposed naming the pesantren they led Darul Ulum (literally, the house of knowledge).

In 1958, the Pesantren Darul Ulum was shocked by the death of Kiai Dahlan Kholil on the 16th of March, followed by that of Kiai Romly a month later. The same held true when Kiai Ma‘shum Kholil died in 1961. The Pesantren Darul Ulum lost its three well educated kiai within three years. The new leadership under Kiai Musta‘in Romly, who succeeded his father, Kiai Romly Tamim, was successful in continuing the development of the pesantren. Kiai Musta‘in, assisted by other kiai from his family, not only introduced a more modern system of education in his pesantren but was also successful in establishing a modern higher educational institution. Impressed by what he saw in Germany, Kiai Musta‘in was keen to create modern Muslim intellectuals through the pesantren he led. He established the Universitas Darul Ulum in 1965. Like his predecessor, Kiai Musta‘in was also deeply involved in the tarekat movement.

After Kiai Musta‘in died in 1984, the leadership of the pesantren passed to Kiai As‘ad Umar. In contrast to the kiai in larger pesantren in Jombang, the kiai in the Pesantren Darul Ulum try to introduce tarekat  practice to the santri. Although the santri are not obliged to perform tarekat practices or to become members, the introduction of the tarekat has become a part of their pesantren programs. In the Universitas Darul Ulum, tarekat is also introduced to the students, the majority of whom are santri of the Pesantren Darul Ulum. This introduction is quite limited, since it is confined to providing students with a brief knowledge of tarekat and how it is practised.

The centre of this pesantren is located in Cukir village in the district of Diwek, in the southern part of Jombang. It is around seven kilometres from Jombang city. The pesantren was founded in 1899 by Kiai Hasyim Asy‘ari, the co-founder of NU. It is one of the four largest and most modern pesantren in Jombang. It has had a classical system since 1916 when its founder introduced two levels of classes in which the santri were prepared to take five years madrasa. In the Pesantren Tebuireng there are now some modern educational programs, providing either Islamic or more secular studies. The pesantren also includes a tertiary educational institution, the Institut Keislaman Hasyim Asy‘ari (Hasyim Asy‘ari Institute for Islamic Studies).

The pesantren began when young Hasyim Asy‘ari erected a ten square metre building to teach Islam in a hamlet of Tebuireng. He started his teaching with only eight santri. This was a very difficult task since the surrounding community was only nominal Muslims. The religious services held by Hasyim Asy‘ari were uncomfortable challenge to them. His determination to revitalise Islam, however, resulted in a great success. According to Dhofier (1982) this pesantren only needed ten years to establish its reputation. The number of santri increased to about 200 by 1910. Kiai Hasyim Asy‘ari was then acknowledged as a great Muslim scholar (Hadhro Al-Syeikh) not only because he had successfully developed his pesantren, but also because of his knowledge of Islam. His intellectual genealogy included a number of well known Muslim scholars and many great kiai in Jombang, such as Kiai Wahab Chasbullah of the Pesantren Bahrul Ulum and Kiai Romly Tamim of the Pesantren   Darul Ulum. Other kiai in other areas also learned Islam from Kiai Hasyim Asy‘ari.

Kiai Hasyim Asy‘ari initially learned Islam from his father and other local kiai. He also learned from Kiai Kholil of Bangkalan (Madura), an ‘ulama well known throughout Java and Madura in the 19th century. He also spent nine years in Mecca learning Islam from a great Islamic scholar, Syeikh Mahfuz Al-Tarmisi. His studies with this scholar also introduced him to a tarekat. According to some sources (see Arifin, 1993:72), in addition to the Islamic instruction which Kiai Hasyim Asy‘ari received from Syeikh Mahfuz Al-Tarmisi, he also received ijaza irshad which enabled him to perform the practice of the Qadiriyah Wa Naqsyabandiyah order. Nevertheless he never passed on this ijaza irshad to another kiai, with the result that he did not have followers as other murshid do. Moreover, he did not allow his pesantren to be used as a place for tarekat activities^[16].

Kiai Hasyim Asy‘ari was not alone in managing his pesantren. He was assisted by other kiai close to him, such as Kiai Alwy or Kiai Ma‘shum. Kiai Ma‘shum was the first kiai to introduce the classical system in Pesantren Tebuireng. Secular subjects such as mathematics, geography or Dutch language were taught from 1919. Another kiai who was extremely helpful in managing and modernising his pesantren was his son, Kiai Wahid Hasyim. Kiai Wahid Hasyim recommended that the Pesantren Tebuireng introduce a tutorial system, as a substitute for the traditional teaching system of bandongan. Although not all Kiai Wahid Hasyim's recommendations were accepted by Kiai Hasyim Asy‘ari, madrasah nizomiyah was then established in his pesantren in 1934. This offered secular subjects, which accounted for about seventy percent of the teaching program (Dhofier, 1982:106).

After Kiai Hasyim Asy‘ari died on the 27th of July 1947, his older son, Kiai Wahid Hasyim, succeeded him in leading the Pesantren Tebuireng. The promotion of Kiai Wahid was agreed to by Bani Hasyim (the Hasyim Family), not only because he had a good reputation but also because he was a knowledgable younger kiai. He was a very active kiai, involving himself in the political arena before and after Indonesia gained independence from the Dutch. When Kiai Wahid Hasyim was appointed as the Minister of Religion from 1949 to 1952, he paid much greater attention to national politics than to his pesantren. The Bani Hasyim therefore appointed Kiai Karim Hasyim to lead the Pesantren Tebuireng, as a substitute for his brother, Kiai Wahid Hasyim.

Kiai Karim Hasyim led the Pesantren Tebuireng for only about one year. He was then succeeded by his brother-in-law, Kiai Baidlowi. Kiai Baidlowi was a very knowledgable ‘ulama and the oldest kiai of the Bani Hasyim teaching at the Pesantren Tebuireng at that time. As Kiai Hasyim Asy‘ari had allowed kiai outside his family to lead his pesantren if there was no appropriate member of the family to occupy such a position, the promotion of Kiai Baidlowi presented no problem. It was decided to replace Kiai Karim Hasyim because the Bani Hasyim did not agree with his politics, which leaned towards the Islamic political party of Masjumi. As NU had left Masjumi and transformed itself into another Islamic political party in 1952, the proper political affiliation of the leader of the  Pesantren Tebuireng, in the view of Bani Hasyim, was with the NU political party.

The Kiai Baidlowi leadership of the pesantren did not last long. After one year, he was replaced by Kiai Kholik Hasyim, another son of Kiai Hasyim Asy‘ari, in 1952. This substitution was based on the right of inheritance to the leadership of the pesantren. Despite the unwritten rule suggested by Kiai Hasyim Asy‘ari, which allowed a kiai outside his descendants to lead his pesantren, the promotion of Kiai Baidlowi seemed to be regarded as deviating from tradition, according to which the leadership of a pesantren usually passed from the former leader to his son. There was no conflict in regard to this decision about the succession. Kiai Baidlowi was not ambitious and was content to let Kiai Kholik Hasyim lead the pesantren. Kiai Kholik Hasyim then ran his pesantren for about thirteen years (1952– 1965). He was then succeeded by his brother, Hajj Yusuf Hasyim. Hajj Yusuf Hasyim, despite his busy activities in politics, has led Pesantren Tebuireng since that time. To allow more practical management, the Pesantren Tebuireng is now run by his sons.

The Pesantren Bahrul Ulum is another of the four largest and most modern pesantren in Jombang. It is the oldest pesantren, since it was established in 1825 by Kiai ‘Abdussalam, also known as Kiai Shoichah. It was initially called Pesantren Nyelawe (a Javanese term for selawe, literally 25) or Telu (literally three) because the pesantren had around 25 santri with three buildings. According to an information book written at this pesantren, Kiai Shoichah had royal blood. He was a descendant of the King of Mojopahit, Brawijaya VI. People called this pesantren, Tambak Beras after Kiai Chasbullah assumed leadership. Kiai Chasbullah was a rich man who often stored huge amounts of rice in his storehouse. The village and his pesantren were thus known as Tambak Beras (lit. rice-barn). The name Bahrul Ulum was given in 1967 by Kiai Wahab Chasbullah, who led this pesantren from 1926 to 1971.

At the early stage of the development of his pesantren, Kiai Shoichah was assisted by two santri. These santri were ‘Usman and Sa‘id who were later married to his daughters. ‘Usman married Layyinah, while Sa‘id married Fatimah. After they assumed kiaiship, Kiai ‘Usman then married his daughter, Winih, to his student, Asy‘ari (the father of Kiai Hasyim, the founder of the Pesantren Tebuireng). But, the continuation of the Pesantren Nyelawe was passed on through Kiai Sa‘id. Kiai Sa‘id had four children, one of which was Chasbullah. Chasbullah then became a famous kiai, and was regarded as the founder of the Pesantren Tambak Beras.  

(Source: Pengurus Pondok Pesantren Bahrul Ulum, 1994:37)

The increase in number of Kiai Shoichah's santri forced Kiai ‘Usman and Kiai Sa‘id, his sons-in-law, to assist him either in managing the pesantren or teaching the santri. Both of these younger kiai were advised to establish other pesantren nearby. Since the pesantren of Kiai ‘Usman and of Kiai Sa‘id were part of the Pesantren Nyelawe, some of the santri of Kiai Shoichah either lived in these pesantren or learned Islam from these kiai. After Kiai Shoichah died, the management of the Pesantren Nyelawe was centred on the pesantren of Kiai Sa‘id and Kiai ‘Usman. Kiai Sai‘id was assisted by his son, Kiai Chasbullah, in managing and developing his pesantren. Kiai Chasbullah then united the two pesantren after his father and Kiai ‘Usman died.

The most well known kiai of this pesantren was Kiai Wahab Chasbullah. He continued the leadership of the pesantren after his father, Kiai Chasbullah, died. He introduced a classical system while his father still led the pesantren. He established a three year madrasa in 1915, one year after he returned from Mecca; and in 1932 he provided the madrasa with a five year learning system. What made Kiai Wahab Chasbullah well known was his involvement in national politics, representing the NU. He was deemed to be a co-founder of NU^[18]. After Kiai Wahab Chasbullah died in 1971, the pesantren came under the leadership of Kiai ‘Abdul Fatah. Kiai Najib Wahab continued to lead the pesantren after Kiai ‘Abdul Fatah died in 1977. Since 1987 the leadership of the pesantren has been held by a Dewan Majlis (a joint leadership council) which relies on modern management practices with several kiai as advisers.

Like other modern pesantren, the Pesantren Bahrul Ulum has always been attended by santri of various backgrounds. It had around 2,503 santri in 1994. According to the data collected by this pesantren, around 90 percent of the santri come from places other than Jombang. The pesantren runs both a modern and a traditional system of schooling. The modern schooling is funded by the pesantren with little support from the government. In 1984, the pesantren established a tertiary educational institution.